Redwood Barn Nursery

Fruit trees are in!

2012-01-07T10:57:00.000-08:00

After The Frost: What To Do?

2011-12-29T16:58:00.000-08:00

plus: Planting for Winter Color

We have had a lot of frost this year! According to the weather records from the station west of UC Davis, there have been 18 mornings cold enough for frost since Nov. 1. This is a pretty typical La Niña pattern. Low rainfall = low dew points, less fog, and more frost on a clear, still night.

Lowest readings have been the mornings of Dec. 24 and 25 when that weather station recorded 24 degrees. Ordinarily temperatures that low could be expected to do pretty serious harm to citrus and other subtropicals. But damage so far has been minimal.

Microclimates are making a big difference. The areas up against your house on an east-facing or south-facing walls are several degrees warmer due to heat stored during the day, and are warming up quickly when the sun comes out. Cold damage on a plant is a combination of absolute temperature and duration. These frosts have been cold, but short duration.

Dry soil can lead to further damage from cold as plants desiccate. We are way behind on rainfall, with less than half of normal to date. Water newly planted plants, those in containers, and larger citrus and subtropicals. You can simply run your sprinklers through one cycle, or give each plant a quick soaking with a hose.

If your plant is showing damage, it's best to just leave it alone for now. Cutting back frosted leaves and stems opens the plant up to further damage. Those wilted, curled leaves, in some cases, actually provide a small measure of frost protection for parts of the plant further down. I prefer to wait until spring and let the plant begin to grow before pruning. Let the plant tell you how far to cut it back; just cut to the new growth when it occurs.

You've probably already figured out that your summer annuals won't be coming back. Impatiens, coleus, marigolds, and their ilk are dead. Don't rush to rip out begonias, as they often do resprout in spring from the base. Winter annuals are impervious to the cold. Pansies and violas, snapdragons, stock, ornamental cabbage and kale, and paludosum daisy may bend over with frost, but will perk right back up when the sun is upon them. Winter-flowering perennials such as cyclamen are also unaffected. Likewise in your vegetable garden: the salad greens, broccoli, cabbages, onions, and others are all perfectly hardy.

[Science quiz! Why do some plants survive cold and other not? Different chemicals in the leaves and stems. Plants that evolved in colder regions make natural anti-freeze.]

Some common questions:

Should I keep the plants covered?

Only if the material you used allows light to penetrate. Covering a plant with a sheet or blanket has two drawbacks. Each point of contact with the leaves and stems is likely to result in damage as the cold transfers through the cloth. And the exclusion of light for more than a day or so will cause the plant to start dropping leaves.

Should I sprinkle the foliage to protect it?

This common agricultural practice is not practical for homeowners. You need continuously freezing layers of ice forming on the foliage through the freezing period (early morning before dawn). Sprinkling the leaves once doesn't make any difference.

Should I pick all the citrus fruit?

Only if you want a bunch of under-ripe fruit. Citrus don't ripen any further once picked, and most varieties aren't ready yet. Your Satsuma mandarins are ripe, but that also happens to be one of the hardiest citrus varieties. Lemons, navel oranges, and others are still tart. I'd be surprised if a couple of cold mornings have damaged the crop. Stripping the tree was appropriate in 1990 and 1998, when we had epic freeze events. A hard frost of a couple day's duration? I prefer to leave them on the tree.

Do I need to protect my rose bushes?

No. Roses are hardy here.

On a more cheerful note, how about some color in the garden in mid-winter?

Cyclamen

We are fortunate to live in a gardening climate where we can have color year-around. The afore-mentioned winter annuals can be planted even in the coldest weather, and will continue to bloom into spring or even early summer. Pansies and violas are most popular due to the color range and profusion of bloom over a long period.

There are a few perennials that bloom mid-winter. Examples include bergenia, gazania, hellebores, and red-hot-poker (Kniphofia hybrids). Take a quick walk through the Ruth Storer garden at the west end of the UC Davis Arboretum to get some ideas; it is an all-season resource. On a recent visit the Kniphofia variety called Christmas Cheer was in full bloom.

Certain shrubs give us reliable winter flowers. Examples include the golden bush daisy (Euryops), laurustinus (Viburnum tinus), Oregon grape (Mahonia), rosemary, and the extra-fragrant sweet Victorian box (Sarcococca ruscifolia). Some winter-bloomers with special requirements include camellias and winter daphne. Well worth the effort, but ask before you buy.

We also enjoy the colorful foliage of a number of evergreen shrubs. Cold weather leads to interesting chemical changes within the leaves of certain plants, leading to bright pigments that are less obvious or missing in warm weather. Just part of the background shrubbery much of the year, these stand out in cold months. Examples include the common heavenly bamboo (Nandina domestica) and the purple hopseed bush (Dodonea viscosa purpurea).
One deciduous shrub with late-season color is Japanese barberry (Berberis thunbergii), whose leaves turn bright red in fall and then hang through December. It grows to five feet tall or so. A dwarf cultivar called Crimson Pygmy only grows to 2 to 3 feet tall and wide.

Colorful winter fruit is a bonus of citrus, and the hardiest one is also the most ornamental: the kumquat. Not everyone likes to eat the tart/sweet fruit. The peel is sweet and edible, the flesh is tart. So to eat a kumquat, you pop it in your mouth whole and chew it up. But even if you don't favor the flavor, you can appreciate the abundant bright golden fruit out in the yard. Kumquats are cold-hardy well into the teens, have fragrant flowers in the summer, and the plant has dense foliage and grows upright.
Many ornamental shrubs have colorful winter fruit, including natives such as Toyon (Heteromeles arbutifolia) and Coffeeberry (Rhamnus californica). There are great examples in the Arboretum near the road which goes to Mrak Hall. The non-native heavenly bamboo, mentioned above, also bears red winter fruit with the colorful leaves.

Is it ok to plant these selections now? Sure, if your soil is workable. Digging in muddy soil is bad for the soil structure. But one silver lining to our dry season is that soil can still be turned and proper planting holes can be dug. If not, just hold the plants in the pot until spring. Don't forget to water them if we don't get rain!

For statewide weather data, go to the UC Davis IPM web site and look for the "Weather, models, and degree days" link here. I use the Davis.A station.

Brugmansia in the UC Davis Arboretum after a frost.

Angel's trumpet

Taken from the building side of the bush, this photo shows the effect of microclimate. The outer, exposed branches have been damaged, with leaves and flowers killed. Branches closer to the warm building survived. What to do? Just leave it alone. Damaged leaves will fall, and new growth will emerge somewhere along the branch in spring. Then you can cut it back safely.

Viola

Who doesn't like pansies and violas? The familiar blooms come from October through May in a wide range of colors. Violas (shown here) are smaller than pansies and hold their heads up better in rainy weather.

Bergenia crassifolia Winter-blooming bergenia

Shade-tolerant Winter-blooming bergenia (Bergenia crassifolia) carries its pink blooms above the foliage from January through early March. The large leaves are attractive year-around, mixing well with ferns, hellebores, Japanese maples, and other shade lovers. Will tolerate some drought.

Gazania---

Helleborus

'Cherry Blossom'
Once upon a time, hellebores were expensive and hard to find. Then growers figured out the trick to mass propagation, and plant breeders had fun creating new colorful hybrids. Different species bloom at different times, but all during winter or spring. This two-tone cultivar is called Cherry Blossom. Hellebores love shade, regular watering.

Kniphofia

'Christmas Cheer'
Red hot poker
One of those perennials your grandmother grew, which then fell out of favor. But now gardeners are rediscovering the hardiness, drought-tolerance, and long bloom season. These plants are in full sun, with little water, in the UC Davis Arboretum.

Euryops pectinatus
Golden bush daisy

A reliable winter and spring flowering shrub. Sun-loving, drought-tolerant, and unaffected by frost. They may begin blooming as early as fall, and continue usually until hot weather arrives in May. There are green-leaf and grey-leaf forms.

Rosmarinus officinalis

'Miss Jessups'
Rosemary

Common garden rosemary is a winter bloomer! There are upright as well as spreading varieties, and all have blossoms in shades of blue. They are tough and drought-tolerant, and all types can be used in cooking.

Berberis thunbergii 'Atropurpurea'
Redleaf Japanese barberry

A deciduous shrub, but in our climate it loses its leaves very late in the season. First they turn bright red, then they hang on the branches for several weeks. Shown here in mid-December. Barberries make formidable barrier plants, bristling with spines. Best with regular watering.

Nandina domestica
Heavenly bamboo

Winter leaf color of Nandina (Heavenly bamboo) is one of its great garden features. Lush green leaves turn red with the first cold nights. Berries are a nice bonus.

Dodonea viscosa

'Purpurea'
Purple hopseed bush

A tough, drought-tolerant evergreen shrub that grows quickly to 8 to 10 feet tall, half as broad. It has purplish-green leaves that turn intense burgundy when cold weather comes. Excellent with California natives, as it can live with little or no summer watering once established.

© 2011 Don Shor, Redwood Barn Nursery, Inc., 1607 Fifth Street, Davis, Ca 95616

www.redwoodbarn.com

Feel free to copy and distribute this article with attribution to this author.

2011-12-14T10:23:00.000-08:00

Another nurseryman's take on the garden business...
http://www.gardencentermagazine.com/blogs/guest-blog-greg-draiss-about-trends.aspx

Tree Associates Blog

2011-12-09T15:47:00.001-08:00

Happy to see that John Lichter's Tree Associates has gone to a blog format. John and his associates are very knowledgeable about trees. This should be one to bookmark!

Tree Associates

Do you have an Android?

2011-12-08T20:00:00.000-08:00

Don,
sorry for the unsolicited mail but I noticed an article on your blog today about frost and wanted to see if there was any chance you would be willing to mention an app I have written for android mobile phones. I realise it's a bit cheeky asking for free advertising but as you'll see, I put the app on for only 99p and will never make a fortune from it...but would like to see it become a little more popular given the number of hours I've put into it ! I originally developed it purely for myself, after losing a lot of stuff to a late frost in the UK, then realised others might find it useful so published it on the android market to see what happened...it's been quite interesting to see who downloads it (I have about 120 users now and many aren't gardeners at all !)

It's the only app on android that will notify you based on the weather forecast, if the temperature is due to drop below the temperature you set (I didn't need yet another weather app...I just wanted something that warned me when there was going to be a low temperature...rather than me have to remember to check the forecast every day).

Many thanks for taking the time to read this, and any feedback or suggestions you might have are most welcome.

many thanks,
Antony Cook

ColdSnap! Frost Alarm

Frost warning? Freeze Warning?

2011-12-05T13:32:00.000-08:00

Written for the Davis Enterprise, November 24, 2010

Click on any image for a larger version

"He comes, - he comes, - the Frost Spirit comes!

On the rushing Northern blast ... " John Greenleaf Whittier

This week marked the first National Weather Service frost warning of the season. Our main frost season typically runs from Thanksgiving through Valentine's Day. There have been frosts after Feb. 14, and occasionally before the last week of November, but those have been infrequent and of little consequence.

What weather conditions lead to a frost warning?

The poem was a bit of hyperbole on Whittier's part: frost doesn't "rush" in, it forms under still, clear skies. But he had a point. Frost can occur after a cold air mass, usually a storm, moves through the region. Cloud cover during the day gives way to clear skies in the early evening. As heat is lost to the sky, the surfaces cool rapidly. When the air temperature gets to the dew point, fog forms. When surface temperatures drop below freezing, frost forms. [Note that the air temperature you measure or see online may still be above freezing; it is the surface temperature that matters.]

When the surface reaches 32 degrees, the layer of water vapor molecules in contact with that surface freezes, and then the layer above that, and so on. Frost doesn't fall from the air, it freezes directly on a surface. Some surfaces cool faster than others. The metal on your car may show frost by midnight; bare soil by dawn, while grass might not even reach freezing that same morning. It all has to do with how efficiently the particular surface conducts heat.

What would prevent the frost?

"The Frost performs its secret ministry,

Unhelped by any wind." - Coleridge

Clouds and fog prevent frost by trapping the outbound heat. Light winds mix the warmer air from above back down to ground level. This is the principle behind the giant fans you see on the edges of vineyards in Napa Valley.

What's the potential for harm in the garden?

Leaves lose heat to the sky! Damage to a plant depends on the structure and contents of those leaves. Soft, succulent plants such as Impatiens turn to mush as the cells rupture. Hardy plants contain sugars and other chemicals that act as natural antifreeze.

A frost is not a freeze.

First, don't panic. If a plant is considered hardy here, damage will be cosmetic. The leaves may look ugly, but the plant will survive. It is a freeze that we are concerned about: a period of colder temperatures when a very cold air mass moves over the region.

Our biggest risk is mid-December to mid-January. Temperatures below the mid-20's are unusual here and spell trouble for many plants. On December 23 1990 we reached 16 degrees. The morning of January 14 2007 got to 20 degrees.

Freeze damage is a matter of how cold we get, for how long. That morning in 1990 was the start of a ten-day episode, with each successive day causing further tissue damage to leaves, shoots, and eventually the woody parts of plants.

Which plants are we going to lose on a frosty night?

Summer annual flowers, such as this showy planting of Impatiens in front of Lyon Real Estate office on 2nd Street, will likely be toast after a night or two of light frost. But there are plenty of winter annual flowers we can plant in their place. Pansies [shown at right] and violas, snapdragons , cyclamen and primroses all give winter and spring color without any concern about cold weather.

Pansy 'Delta Premium' -- no need for protection!

Which plants should we protect from frost?

Some succulents such as jade plant, some aloes, and kalanchoes.

Tender subtropicals such as hibiscus and mandevilla.

Semi-tender subtropicals such as bougainvillea, Guatemalan avocado, Mexican lime, young lemon and citron trees.

Which plants should we protect from a freeze?

Older lemons, other young citrus trees, Mexican avocado, geranium (Pelargonium). Blossoms of Lilac vine (Hardenbergia), which bloom in late winter, can be saved by covering the plants.
As temperatures drop further we may get concerned about some of the hardier citrus. Tangeloes, grapefruit, navel and Valencia oranges can be damaged in the mid-20's.

There are many subtropical plants I don't worry about. Brugmansia, lantana, and passionflower may defoliate, or be partially killed, but will recover. Once you get used to the winter appearance of these semi-tender plants, you'll worry less. Just think of them as deciduous. Leave them alone: wait until new growth begins in spring before you cut off the frost-burnt parts.

Passiflora 'Coral Glow'

We grow many subtropical plants in Northern California. Some are badly harmed by freezing weather, while others (such as the Coral Glow Passionflower shown here) re-sprout readily in spring. Temperatures in the upper 20's will damage the leaves and cause some die-back, but the plants will recover. Lower temperatures may completely kill the tops. Damage can be reduced by taking simple measures to trap or provide heat to the plant.

Some citrus are much hardier than lemons and limes. My mandarins and kumquats have been through major freezes with minimal damage. Fruit of Satsuma mandarins may be harmed at very low temperatures, so you might harvest the fruit if extreme cold is predicted. But citrus fruit won't ever get any sweeter once you pick it, so stripping the tree is a last resort.

There are two main ways to protect plants:

Trap heat.

A plant under an overhang is safe, as the building will keep the heat from escaping to the sky. Frost blankets, which are made of light fabric that allows light in, act to create a mini-greenhouse. Anchored with metal pins, these are the simplest way to provide protection.

Using frost blanket to protect fruit on a mature lemon tree.

Provide heat.

Old-fashioned holiday lights generate enough heat to keep the plant warm. Even a 40-watt bulb on a shop light fixture, attached at the base of the tree (grounded outdoor-rated only!) may be enough for a small tree. Combined with the frost blankets, you can get a few degrees of warmth, enough to keep the local temperature above freezing.

Finally, plants in containers may be damaged by desiccation (cold-induced drying) during freezing weather. Keep your outdoor containers watered during the winter! They won't need it very often: once every week to ten days should be fine if we don't have rain.

Poems:

The Frost Spirit, by John Greenleaf Whittier

Frost At Midnight, by Samuel Coleridge

(Yes, Dr. Hayden, I still read poetry!)

Choosing shrubs to use less water

2011-11-24T14:28:00.000-08:00

Written for the Davis Enterprise, November 25, 2011

Click on any image for a larger version

This month we continue our theme of reducing water use in the landscape. It is estimated that 80% of residential water use goes to yard watering.

Last month's (October 2011) column focused on water use by lawns.

To recap:

* reduce total square footage of grass;

* plant seed of grass species that can use less water, such as fine fescues;

* replace some lawn areas with lower-water ground covers.

This month I'm going to focus on shrubs that make the backbone of the yard, providing privacy, attractive foliage, and seasonal flowers. Aesthetically, it is best to repeat one type, rather than having a hodge-podge of mixed foliage, and then add some of the others for contrast. If you have existing shrubs, interplant some of these listed, do some careful pruning for a couple of years, and then remove the more water-intensive types after the new ones grow up a bit.

What about your existing shrubs?

We see a lot of plants with problems resulting from watering too often, so just by watering correctly you can reduce your water bills and have a healthier landscape. Water slowly, deeply, and infrequently. When we ask about watering schedules, it is common to learn that shrubs are being watered 3 to 4 times a week. That's too often! And they're being watered for ten or fifteen minutes. That's not long enough!

Did you know that many or most of your landscape shrubs could go a week or more between waterings if you irrigate deeply enough each time? Many can go much of the summer on just a few deep irrigations, and some need no summer water at all!

Careful plant selection is another approach to reducing your water bill.

Choose trees, shrubs, and flowering plants that can live with reduced watering.

Here is a list of some shrubs that could be watered as little as once a month once established (which means after the first summer). Some require drought: California natives are sensitive to crown rot if watered too often. The others can be watered more often if necessary. All are evergreen unless noted as deciduous.

* Botanical name: Buddleia davidii

Common name: Butterfly bush

Butterfly bushes love sun, attract butterflies and hummingbirds, and bloom all spring and summer. There are many varieties, ranging from 6 feet to more than ten feet tall, with purple, pink, violet, or white flowers.

* Callistemon citrinus

Bottlebrush

Fast-growing, somewhat open growth habit benefits from pinching and shaping. Showy red flowers, off and on through the year, attract hummingbirds. Prone to iron chlorosis when irrigated.

* Chaenomeles japonica

Flowering quince

The first shrub to bloom in the late winter! Some stay under 3 feet; several varieties grow to 5 - 6 feet or more. Fruit, if any develops, makes unique, aromatic jelly. There are white, pink, orange, and red varieties. Deciduous.

* Dodonea viscosa 'Purpurea'

Purple hopseed bush

Fast-growing quick screen. Bronze foliage turns dark purple, almost maroon, in winter. Fairly open habit, but can be sheared for greater density.

* Eleagnus x ebbingei 'Gilt Edge'

Elaeagnus

Upright growth habit, thornless. Silvery leaves with bright golden margins. Flowers attract beneficial insects; edible fruit attracts songbirds.

* Escallonia rubra

Red escallonia

Big shrub with dark, glossy green leaves and dark red flowers. Leaves have a resinous odor. Flowers attract hummingbirds.

* Garrya elliptica

Coast silktassel

Dark green foliage on a large, dense shrub. Long tassels of flowers in late winter are interesting and attractive. 'James Roof' is a shorter, more compact variety than the species. This California native is best unirrigated.

* Grevillea species and varieties

Australian natives that have odd-shaped, showy pink or red flowers over a long season. All attract hummingbirds. There are dozens of varieties; check descriptions for winter hardiness in our area.

* Heteromeles arbutifolia

Toyon

Grows 2 to 3 feet a year, eventually more than ten feet tall. Flowers are very attractive to beneficial insects. Beautiful shiny red fruit hangs on into winter, attracts birds. There is a yellow-berried variety called Putah Gold, introduced by the Arboretum. This California native is best unirrigated.

* Lavatera maritima

Tree mallow

Also sold as L. bicolor. Fast grower. Gawky growth habit--shear it occasionally, or prune it back severely in the spring or fall. Flowers are light pink with dark rose veins. Blooms all summer.

* Rhamnus alaternus

Italian buckthorn

Fast-growing, upright, with dark shiny green, dense foliage. Flowers attract beneficial insects; small berries (you don't see them) attract songbirds. Great for a quick hedge for privacy. Don't overwater. The selected form John Edwards is more resistant to crown rot. Variegata has cream-variegated leaves, is slower growing and smaller.

* Rhamnus californica

Coffeeberry

Slow-growing native cousin of the buckthorn that looks very much like Toyon (Heteromeles), with similar, larger red berries in winter. Variety called Leatherleaf has larger, darker leaves. This California native is best unirrigated.

* Xylosma congestum

Shiny xylosma

One of the toughest landscape shrubs around. Tolerates heat, even reflected off a west wall; drought; shade. Can be trained into a beautiful small tree, clipped as a formal hedge, or trimmed for an informal screen.

Some plants usually grown as trees can be grown and pruned as shrubs.

* Arbutus unedo 'Compacta'

Strawberry tree

Showy flowers and fruit, beautiful bark like madrone. Fruit litter may be a problem, but it is edible and birds like it. Heat and drought tolerant. Grows 1 - 2 feet a year. Easily kept at 6 to 8 feet with one annual pruning.

* Ceanothus 'Ray Hartman'

Wild lilac

This variety grows to 10 - 15 feet or more. Attractive, large shiny leaves. Pretty medium blue flowers in large clusters in spring. Water deeply and very infrequently in summer.

* Citrus hybrids and varieties

Many varieties make excellent patio or container trees, or can be clipped as shrubs. Meyer lemons, kumquats, and satsuma mandarins are naturally dwarf. Minneola tangelo is especially attractive.

* Cotinus coggygria 'Royal Purple'

Purple Smoke tree

Purple leaves and purple flowers make a striking contrast with grey or glossy-leaved plants. Very tolerant of drought and heat. Gets iron chlorosis if irrigated heavily. Deciduous.

* Feijoa sellowiana

Pineapple guava

Plant named varieties if you want reliable fruit production. Edible flowers! Very drought tolerant. Fuzzy grey-green leaves make a nice contrast with red-leaved or shiny-leaved shrubs.

* Junipers:

Juniperus chinensis 'Torulosa' (also called 'Kaizuka')

Hollywood juniper

Striking, contorted upright growing juniper with dark green foliage. Excellent specimen plant. Very tough, drought-tolerant.

Juniperus scopulorum 'Gray Gleam'

Gray Gleam juniper

Other varieties of this species (Cologreen, Pyramidalis, Blue Haven) have similar growth habits. These are all pyramidal-shaped, upright growers useful in formal plantings. Wichita Blue is more cone-shaped. Very tough, drought-tolerant.

Juniperus virginiana 'Skyrocket'

Skyrocket juniper

Upright column like an Italian cypress. Useful for a formal effect in smaller gardens. Very tough, drought-tolerant.

* Laurus nobilis

Grecian Bay laurel

The bay leaf used in cooking. Very versatile garden plant. Large shrub, eventually growing to 30 feet +, but very upright habit and ease of pruning make it manageable. Will grow in total shade to full sun. Drought tolerant. Very easy to keep in a pot for years.

* Punica granatum

Pomegranates

All pomegranates tolerate heat, wind, drought, poor soil. Great choice for west exposure. Fruiting forms yield large crops here with no effort on your part. Fruitless forms with showy flowers are available and are equally tough.

* Vitex agnus-castus

Chaste tree

Light blue flowers; white form also available. Fast-growing large shrub or small tree with light green palmate leaves. Tolerates heat, drought; will grow in partial shade.

Previous (October 2011) article: Easy Steps to Reduced Water Use

Here are some lists of drought-tolerant plants

Buddleia davidii and hybrids

Butterfly bush

Buddleia hybrids have become very popular for their long season of bloom and attraction to hummingbirds as well as butterflies. Most have a somewhat open habit and benefit from light pruning for greater density. Shown here is the variety Royal Red.

Callistemon citrinus

Lemon bottlebrush

This is the most commonly grown species of Callistemon. The common name comes from the lemon scent when you bruise the foliage. The bright red flowers appear every two to three months throughout the year, often including the winter months, and attract hummingbirds and bees. Watering too often leads to iron anemia; this plant prefers very infrequent irrigation

Eleagnus ebbingei 'Gilt Edge' has creamy-margined leaves on an upright shrub to 8 to 10 feet or taller. Edible fruit is popular with birds.

Feijoa sellowiana, Pineapple guava, has leaves that are green above, grey below. Flowers and fruit are edible.

Grevilleas are Australian shrubs with needle-like foliage and interesting, showy flowers over a long season. Hummingbirds are very attracted to Grevilleas. Shown here is the variety Scarlet Sprite.

Heteromeles arbutifolia, our native Toyon, is aptly called Christmas berry for the red fruit in wintertime. A yellow variant, Putah Gold, can be seen in the UCD Arboretum. Toyons grow at a moderate rate to ten feet or more. The flowers attract beneficial insects, and the berries attract songbirds.

Laurus nobilis, Grecian bay laurel, has shiny leaves that are so iconic that similar leaves on other plants are called 'laurel-leaf'. Crush the leaves to get the familiar pungent bay scent; this is the culinary bay.

Lavatera bicolor, Bush mallow, is a hibiscus relative that is cold-hardy and drought-tolerant. Showy pink-lavender blooms over a very long season.

Rhamnus alaternus 'Variegata', the variegated Italian buckthorn, has an upright growth habit. Songbirds like the tiny fruit.

Xylosma congestum

Shiny xylosma is one of the toughest, most useful evergreen shrubs around. Extremely tolerant of heat and drought, ok with some shade, it can be clipped as a hedge or even trained as a small tree. Variety Compacta is denser, has thorns.

Easy Steps to Water Conservation

2011-11-05T17:14:00.000-07:00

Easy Water Conservation.

Water rates are in the news, and we are getting more interest in lower-water landscaping. It is estimated that 80% of residential water use is outside, with a very large percentage of that due to the lawn.
There are a number of easy ways to reduce your landscape water use.

First is to water correctly.

Water deeply, and as infrequently as possible for the types of plants you have chosen. For example, nothing needs water more often than twice a week during the summer here. Established shrubs and trees can often be watered once a week or less, if they get a thorough watering each time.
Most people could easily reduce their water use by 20% or more just by watering more deeply but less often.

Second is to zone your plants by water need.

You may wish to have a tropical oasis or fern grotto, so put those plants together in one area. You might want a lawn area. Your shrubs and trees don't need to be watered as often as those other types of plants.

Third is to reduce lawn area if possible.

Your lawn, properly watered, uses about 1000 gallons per 1000 square feet each week. And many people apply much more water than needed. Some turf species are more tolerant of infrequent watering, but in nearly any case the lawn is the highest water user in the landscape.

"Form follows function," Louis Sullivan said. Let your landscape form follow the actual use patterns of your family. Lawns are for kids and dogs, and are usually unneeded in front. Put lawn where you will use it, not just where you'll look at it.

Fourth is to choose plants that use less water.

For this article I'll focus on ground covering plants that can replace your lawn and use less water. First is the botanical name, then the common name if there is one. Landscape designers can choose from among Mediterranean plants, natives of South Africa and Australia, California natives, and more.

Herbaceous (soft) ground covers

* Aptenia cordifolia

Red apples

Popular succulent with red flowers. Rampant! Blooms freely, smothers weeds. Bees love it. Frost turns leaves to mush, but it quickly resprouts in spring.

* Dymondia margaretae

Very tough, low-growing ground cover for dry areas. Little yellow flowers. Some die-out if overwatered. May be damaged in cold winters, but recovers. Excellent between step stones.

* Epilobium species (formerly Zauschneria)

California fuchsia

Several species and varieties, ranging from 6" to 2'+. Bright orange-red flowers in late summer through fall attract hummingbirds. Tolerate drought or infrequent watering. Will grow in very light shade or full sun. Cut back when they look rough in the winter.

* Festuca ovina glauca

Blue or Grey fescue

Little tufts of silver grass foliage to about a foot tall. Single plants make a clump. Planted on 6 to 12 inch centers, makes an informal grey meadow.

* Gazania hybrids

G. leucoleana forms spread, have silver foliage, yellow or orange flowers. Clumping types have showier flowers, but don't cover ground as thoroughly--better in perennial borders.

* Lantana sellowiana

Trailing Lantana

Lavender flowers all summer and fall; there is a less-common white form. Grows to a foot tall, with each plant spreading 6 - 10'. Very tolerant of heat and drought.

Cut back in spring to remove frost damage. Also sold as L. montevidensis.

* Rosmarinus officinalis

Rosemary

There are selected forms with spreading habit, and others that are upright. They vary in height (1 - 2 foot +), depth of blue flower color. All can be used in cooking.

* Sedum confusum

Golden sedum

Dense, slow-growing succulent with shiny yellow-green leaves and showy yellow flowers. Great for edging; mix with grasses, use in pots, around stepstones. Takes sun or moderate shade, drought or average watering.

* Sedum spurium

Dragon's Blood sedum

Very low succulent grown for attractive reddish-bronze leaves. Tolerates sun or some shade; average watering or drought. Color intensifies in winter. 'Tricolor' has leaves that are white, pink, and green.

* Zoysia tenuifolia

Korean grass

Very dense, interestingly lumpy grass ground cover with needle-fine leaves. Dormant (brown) in winter. Very tough.

Vines that are planted as ground covers.

These are especially drought tolerant.

* Sollya heterophylla (fusiformis)

Australian bluebell creeper

Small, with dense, tiny, shiny leaves. Can be used as a ground cover. Grows slowly to about 6' tall when supported; 1 - 2' as a ground cover. Nodding blue flowers in summer; 'Alba' has white flowers. 'Boddy's Choice' is a very slow-growing type grown as a shrub or ground cover. Quite shade or sun tolerant, will grow under Eucalyptus trees.

* Trachelospermum asiaticum

Asian jasmine

Nearly always grown as a ground cover. Hardly ever flowers; grown for shiny leaves and exceptional durability. Can be tied up as a vine, but doesn't twine.

* Trachelospermum jasminoides

Star jasmine

Super fragrant flowers in May and June. Tolerates heat, cold, sun, shade, poor soil, drought or watering.

Shrubby ground covers

There are many woody plants that spread across the ground, making a shrubby ground cover. These tend to be two to three feet high.

* Artemisia 'Powis Castle'

Vigorous spreader with silver, ferny foliage. Extremely tolerant of heat, drought; ok in partial shade. Leaves have a strong medicinal scent. Completely shades out weeds. Can cover quite an area!

* Ceanothus species

Wild lilac

Several low spreading varieties are used as ground covers. Attractive shiny leaves; pretty blue flowers in spring. Ground cover forms range from a few inches to a few feet tall, spreading several feet. Don't plant where they'll have to be pruned. Water deeply and very infrequently in summer. California native.

* Euonymus fortunei 'Emerald Gaiety'

Variegated Wintercreeper

Low grower creeps along the ground, or can be clipped as a shrub. Very tough, tolerant of shade or sun. Flowers aren't noticeable. White portions turn pretty pink color in winter.

* Mahonia repens

Creeping mahonia

Shiny leaves, yellow flowers, shade tolerant. Slow to get going, but persistent and tough.

* Ribes viburnifolium

Catalina perfume, Evergreen currant

Will grow in considerable shade. Spreads steadily to make an attractive ground cover. Fragrant foliage. Very small light pink flowers in winter attract hummingbirds; red berries attract songbirds. California native.

How to do it.

You will need to kill out your grass somehow first. You can spray with an herbicide, or cover the area with black plastic for several weeks. Get your turf species identified since some grasses can be persistent and troublesome, especially bermudagrass. The plants listed don't need any special soil preparation. Rototilling will make planting easier. But you can just dig individual holes for the small plants.

Watering of the new plantings can be done with your lawn sprinklers, but you will water far less often. Or you can convert your system to drip irrigation. You may want to ask a landscape contractor for help if you do that.

Unplanted areas can be covered with a thick mulch to retain moisture and prevent weeds. Any bark or compost product can be used. Local rock yards can deliver bulk quantities at a reasonable price.
You need to do a little math to order the right amount of mulch. For two inches of mulch on 100 square feet, you need 16.7 cubic feet (100 divided by 6 = 16.67 cubic feet). There are 27 cubic feet in a cubic yard.

Green is good, but green lawns are high water users. So reducing your water consumption often begins right in the front yard, by choosing water-thrifty plants.

Some choices:

Aptenia cordifolia, commonly called Red Apples, is a fast-spreading succulent ground cover that smothers weeds. The red summer-long blossoms attract bees. It is best planted in spring or summer, as winter cold often causes top damage. But it recovers even from severe freezes.

Artemisia Powis Castle is a hybrid sagebrush. Tolerant of sun, drought, reflected heat, poor soil. It is a spreading shrub that suppresses weed growth. A single plant can spread six to eight feet or more.

Ceanothus is our native wild or mountain lilac. Forms of the shrub range from trees to a number of cultivars with low, spreading growth habit. The latter can be used as ground covers in very dry landscape plantings. Caution: Ceanothus need good drainage and cannot tolerate regular landscape irrigation.

A very tight-growing ground cover in the daisy family, Dymondia margaretae hugs the ground with silvery foliage. The small flowers are yellow. It can take light traffic and is suitable around step stones

Formerly Zauschneria, now Epilobium, commonly called California fuchsia. The late summer and fall flowers are orange-red and highly attractive to hummingbirds. Spreads steadily, though not invasively. Once established it needs little or no summer water.

There are many ornamental grasses that can tolerate, or even prefer, much less frequent irrigation that turfgrass species. Most grow in clumps, so they aren't lawn substitutes. But they can make attractive informal groundcovers. Shown here is Festuca ovina glauca, the blue or grey fescue. Planted close together, the plants look like an informal tall lawn or meadow.

There are trailing and clumping types of gazanias. The clumpers have very showy flowers over a long period, but don't spread enough to considered ground covers. Shown here in a hot, barely irrigated bed, these plants are several years old and blossom from October through May. The low spreading types have silver foliage and hug the ground.

Succulent ground covers can tolerate long periods without water, and Sedums (commonly called stonecrops) are very cold tolerant as well. Sedum confusum, the Golden sedum, can tolerate shade as well as full sun. Golden yellow flowers in spring.

Another sedum is the Dragon's Blood, named for the winter color of the foliage. Shown here is a variegated version: Sedum spurium 'Tricolor'.

Bulbs!

2011-10-19T23:50:00.000-07:00

From the Davis Enterprise, October 28, 2004

Click here for a newer article.

Bulbs have got to be the easiest things we plant in the garden, with the highest bloom:effort ratio. Dig a hole, stick 'em in, cover with soil, and water. The rains come along and do the rest. A few weeks later, up they come--growing and blooming without any more work by you.

Some technical terms.

'Bulb' is a generic term for modified, swollen stems. A true bulb has a set of overlapping, fleshy leaves, usually surrounded by dry, papery skin that protects it from drying. Cut a true bulb in half and it'll look somewhat like an onion on the inside (it'll also be useless after you do this!). Corms, rhizomes, and tubers are other modified stems that are sold as 'bulbs'. The primary function of each is to store food and some water, and each has one or more growing points to start new plants.

Bulbs are perennials, meaning they bloom again after the first season. Some repeat for a few years; others spread for many. Most are cold hardy. Subtropical types (paperwhites, freesias) need winter protection in colder climates, which is important to know if you are sending them as gifts.

How do you plant them?

It's so easy, even a child can do it. In fact, since it's down at the ground level and we are old and stiff, it might be better if a child did it. And bulb planting is a great thing to do with kids; it's nearly impossible to make a mistake.

--Dig a hole a little more than twice as deep as the bulb is tall--a 3" daffodil goes into a 6" hole. I generally dig holes wide enough for several bulbs, since a solitary bulb looks pretty lonely the first season, and plant them 3 - 4 inches apart. Exceptions: iris rhizomes are planted only half-buried. Amaryllis should have their necks exposed.

It's not necessary to mix compost in the soil, but the bulbs will grow and increase more quickly if you do. I've done plenty of bulb planting in soil that was too muddy to mix anything into. They'll be fine.

--Sprinkle some fertilizer in the bottom of the hole. It should have some nitrogen and a fairly high amount of phosphorous (those are the first two numbers on the label). Bone meal is popular due to the high phosphorous content, but it is very, very slow acting. Commercial bulb foods are better (specialty vegetable or flower foods are fine, too).

--Set the bulbs a few inches apart. The point goes up (this may seem basic, but it's pretty important!). Some bulbs don't have an obvious point, so look for the scarred area where roots used to be and put that side down. If you really can't figure it out, put it on what appears to be the side. Ranunculus are planted 'prongs down'.

--Cover with soil and water to settle the soil. That's it! Winter rains will take care of the rest.

It is ok to plant low-growing annual winter flowers right on top of the bulbs: pansies, violas, sweet alyssum, Cyclamen, and dwarf snapdragons all make excellent companions. Low ground covers are also great. The bulbs will grow right up through them to make a spring bouquet.

When to plant?

Anytime between September and early January. Tulips and Hyacinths shouldn't be planted until the soil has cooled, meaning after the end of October. If you find the bag of bulbs in your garage in January or February (we get these calls every year…), plant them. They'll still grow and bloom, albeit a little later than normal, and they'll be back on cycle the next year.

Bulb plants continue to grow for several weeks after they bloom, storing energy for the following year. If you cut off the foliage, you weaken the bulb. So let them die down naturally, though you can tie or braid the foliage if you want to look fastidious.

There's no need to dig up bulbs for the following year. If they've been in the ground for several years and are blooming less and less, it may be time to divide them. Or they may be getting too much shade. In either case, just after (or as) they die down is a good time to dig them. Replant them right away, or store them in the garage until fall.

It used to be recommended to put tulips and hyacinths in the refrigerator for 4 - 6 weeks before planting, but this is unnecessary. Just wait until the soil is cool. Pre-chilling WILL make them break dormancy and bloom all at the same time, so if you want your tulips to flower uniformly go ahead. Do NOT put them in the freezer (we get calls….). That kills them.

Some bulbs are planted in the spring for summer bloom--Dahlias, Gladiolus, and others. We plant those from February into the summer, depending on the type.

Which to grow?

Daffodils and narcissus

are the easiest of the bigger-flowered bulbs. At a minimum, they'll repeat their bloom for a few years. Some varieties will multiply, giving more flowers every year.

A note about the names: all are members of the genus Narcissus. Those with a single large flower (usually with a trumpet) are called daffodils. Those with small flowers in clusters are called narcissus. The fragrant ones with pure white blooms in early winter are paperwhites, a type of narcissus; there is a yellow form and another called the Chinese sacred lily in this category. Europeans call the whole group 'jonquils', but we use that term for a particular, small, fragrant narcissus. Confusing, eh?

Some good daffodil choices:

February Gold (short, very early dwarf trumpet; spreads freely)

Fortune (orange/yellow, spreads vigorously)

Flower Record (white with orange cup)

Ice Follies (white with pale yellow large cup; spreads vigorously)

Mt. Hood (ivory white)

Salome (pink, sort of)

Spellbinder (yellow with white trumpet--striking!)

Good narcissus choices:

Cheerfulness

Geranium

Pheasant Eye

Thalia

Yellow Cheerfulness

Miniatures: Baby Moon

Tete-a-Tete (one of the best!)

'King Alfred' was once a variety of large, yellow trumpet daffodil. It is now a generic name for that type; Unsurpassable and Early Splendor are newer, more vigorous varieties that will repeat and increase somewhat.

Irises

are very easy--both the large-flowered bearded types (grown from rhizomes) and the Dutch irises grown from bulbs. Not generally the most attractive garden plants, but worth the space for fragrance and cutting. There are also cute miniature types which bloom very early, and other species which can grow standing in water. A diverse group.

Tulips, hyacinths, and crocus

will bloom very nicely the first spring. The trick to getting them to bloom in subsequent years is to plant them where they won't get watered in the summer. Tulips with minimal summer water will repeat, though the flowers will be smaller, and hyacinths will increase. These latter have powerful fragrance reminiscent of Grandma's perfume. Giant Dutch crocus tend to peter out after a couple of years, but the species crocus will increase and bloom -- as early as late January here.

Some species of tulips come from Mediterranean climates similar to ours and will naturalize happily here. Tulipa chrysantha, T. clusiana, and others have miniature flowers on short stems. A half-dozen bulbs will increase to 2 - 3 dozen plants within just a few years. Grape hyacinths share the common name but are an entirely different plant (Muscari). These have short, purple flowers and spread very, very freely. The saffron of commerce is Crocus sativus--like some Mediterranean species, it blooms in the fall, and is easy to grow and increase here (coming as it does from Greece, a climate similar to ours).

'Minor' bulbs.

Many of these (i.e., small bulbs and flowers) spread to the point of being almost annoying. Cheap, easy, and prolific. Most can tolerate some shade, will spread through flower borders and even into lawns.

Some old favorites just don't get enough winter chilling to bloom again, including Lily-of-the-valley and Snowdrops (Galanthus). Freesias are popular for fragrance, and very successful. The old-fashioned yellow and white forms are most fragrant.

Good 'minor' bulbs for this area:

Allium (ornamental onions)

Brodiaea

Freesia

Hyacinthoides (Wood hyacinth)

Ipheion (Spring starflower)

Leucojum (Snowflake)

There's no hurry on getting bulbs planted after you buy them. They do their thing with little input from us. They announce the spring with colorful bursts in every hue. These little storage units have everything they need, lying dormant through winter cold or summer drought, ready to expand and grow when conditions are to their liking. What a great adaptation the bulb is--for us!

A Zen Garden In Davis

2011-09-24T10:58:00.000-07:00

Written for the Davis Enterprise, August 25, 2011

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The first clue that this isn't a traditional California landscape is the branch of the Japanese maple peeking out behind the front gate. The drain channels filled with smooth pebbles and elegant "rain chains" are the next signs of some non-Western influences. Small plantings on the side as you walk around the house use gravel and interesting foliage plants.

Crilly Butler and his family live in a house on a quiet cul-de-sac in one of the newer subdivisions of east Davis. Crilly has visited Japan frequently and considers it his second home, and from the time they purchased the bare lot in 1996 they knew they wanted a zen garden. He invited me to view and photograph the garden this spring.

There are several styles of Japanese gardens. Karesansui is the waterless type, generally using limited amounts of plant material, moss (if possible), raked gravel to symbolize water, and groups of rock and stones. Lanterns and pavilions are often included in Japanese gardens of various types. Bamboo, both in plantings and used in construction material, is an important component. Among the many symbolic meanings for bamboo, I found humility, strength, readiness, resilience, simplicity, and more.

To the first-time visitor to a zen garden, it will seem bare. There are rarely flowering plants, and the seasonal changes are subtle. But the lack of abundance focuses the viewer's attention on those simple changes: the flush of new growth on the Japanese maples, the spectacular but fleeting bloom of the wisteria, the seasonal growth of moss on the boulders. In a more complex garden, these would be less individually notable.

From a design standpoint, I was curious how the garden would integrate in a California-style house (at least the exterior) and landscape, including some typical uses such as vegetables and roses. From a horticultural standpoint, my key question was: how did you confine the running bamboo?

Crilly answered my specific questions via email after my visit. As to my design question, it was clear that the zen garden is the strong visual element and that it was carefully designed to fill the key views from the house and patio. The roses and vegetable garden are in an appropriately sunny location off to the east side, just out of view from the house. The bamboo barrier is shown and described below. Note that it would be possible to use non-running bamboo varieties to avoid the confinement issue. Most clumpers, though, have very dense growth habit and might not provide the "see-through" effect that runners provide.

What was your motivation or inspiration for planting a zen garden?

I used to live in Japan, where I studied the martial art Aikido. I met and married my Japanese wife there 28 years ago. I've always loved my "second country", and deeply admire its aesthetic sense. We patterned our Zen garden after our favorite one, found at the famous Kyoto temple Ryoanji.

Did it replace an existing landscape?

We designed and built our Japanese/Western hybrid home on an empty lot, so we were able to plan our landscaping from scratch. Our Zen garden simply replaced barren ground. I think it's quite an improvement!

What year was the project begun, and when was it completed?

We began designing this garden in our minds as soon as we purchased our lot in 1996. After completing the Western rose and herb garden on the east side of our backyard, we started grading for the Zen garden in 2004, though we didn't actually began work on it until 2008. We finished building the border around it, and laying the gravel, in 2009.

Who helped with your design and installation?

My wife and I designed it ourselves, based, as I mentioned, on the garden at Ryoanji. You have to place the rocks just right, so they look as they should from every part of the yard, no matter what the angle. We used orange road construction cones to represent the three "islands", and over the course of 3-4 weeks, kept moving them around slightly until we were satisfied with their placement. My friend Steve Scott carried the large rocks into the yard in a sling attached to one of his small earth-movers, and helped us position them precisely. Other than that, my son Nicholas and I did all the work ourselves.

Tell us about selecting and installing the rocks.

We looked for just the right rocks for quite some time, but couldn't find any that looked like those at Ryoanji. Then we finally stumbled upon some petrified wood boulders at a quarry east of Sacramento. They were unexpectedly perfect!

Where did you buy your bamboo? Why did you select that species (Temple bamboo, Semiarundinaria fastuosa)?

Steve Scott, who's quite a bamboo aficionado, suggested the Temple Bamboo because of its very erect, tall and beautiful culms. We drove his truck to Bamboo Sourcery in Sebastopol, which is an amazing place. They had over three hundred varieties of bamboo there at the time. We planted them about two feet apart in an L-shape along most of our back fence, with the leg extending out about ten feet along the west side of our yard.

Because this species is quite a runner, I trenched around the planting area four feet deep and six inches wide, which I filled with rebar and concrete to keep the bamboo contained. There's nothing worse than seeing your bamboo growing up through the bottom of your neighbor's swimming pool, and I take being a good neighbor very seriously!

Just to verify: your barrier is a concrete trench 4 feet deep, six inches wide, with concrete rebar at 1 foot intervals. Watering is via drip soakers. How often do you run them? What other maintenance do you do?

I ran schedule 80 pvc underground to one end of the bamboo and installed a drip system using three separate soaker hoses winding through the base of the culms end-to-end. It runs for about 20 minutes three times per week in summer, and much less during the other three seasons.

Since bamboo takes in a lot of its moisture through its leaves, I also soak it down top to bottom with a hose periodically, especially when the humidity has been very low for a while. I fertilize every spring with a good lawn fertilizer mixed with FST, since the concrete probably raises the pH of the soil quite a bit. Every winter I thin out the older culms to make room for new growth. I leave the fallen leaves to decompose, rather than removing them, because of their high silica content, which growing bamboo loves.

Some further notes:

A very important part of this barrier system is the maintenance gap between the hedge and the fence. Rhizomes can grow right over a barrier and root, and can readily grow under a fence. Rhizome growth occurs mostly in the spring, so one seasonal walk (sidle, really) behind the hedge to check for escapees will be sufficient. Barriers can be made from very thick polypropylene (60 ml is best). This installation is much more attractive, in my opinion.

Although a zen garden can use considerably less water overall than a more traditional landscape, due simply to the large area without plants, those that are used tend to be high water users. Bamboo and Japanese maples look best if they are not drought stressed.

Japanese maples have some special preferences here. They prefer acid soil with abundant organic material, so turn in lots of planting compost and soil sulfur at the time of planting. While they can take morning sun, Japanese maples will burn in afternoon sun. Finally, true moss is seasonal in our dry, hot climate. Various ground covers can be used as substitutes.

Crilly Butler is a Senior Information Systems Analyst for the California Department of Fish and Game. He also owns the Davis-based Web development company, Develomation.

Steve Scott (http://stevestrees.com/) is a landscape contractor who specializes in moving large field-dug trees.

We get questions...

2011-08-25T15:26:00.000-07:00

In the flower garden:

geranium budworm

eggs of geranium budworm

Something is eating the flowers of my geraniums and petunias!

Geranium budworm is a caterpillar, the larva of a moth, which eats flower buds, petals, and leaves of common geraniums, petunias, callibrachoas, and related plants. It is hard to spot because it turns the color of what it is eating. Most people notice holes in the petals, and then the absence of flowers. Geranium budworm has a broad host range, and is also known as Tobacco budworm and Tomato fruitworm (not to be confused with tomato hornworm, which is more properly called Tobacco hornworm!).

Caterpillars can be controlled with an organic spray made from Bacillus thuringiensis (aka "BT"). The insect must feed on the material, so you have to tolerate some damage before you get control. The adults keep laying eggs all summer, so you have to spray about every week. Consider planting something that doesn't get budworm instead, such as ivy geranium.

Why is my Acanthus dying? It just finished flowering.

Acanthus mollis flowers

We get the same question about Alstroemeria. Both species are growing from a rhizome, and as with many bulb-like plants they have a short dormancy after the bloom. It is normal, but disconcerting. It's a good opportunity to cut the plant back. It will resprout right away.

Alstroemeria

Peruvian lily

In the orchard:

My citrus tree dropped most of the fruit right after it flowered!

Citrus produce an abundance of flowers, but the amount of fruit a tree can sustain is determined by the size and vigor of the tree. Many small fruit drop. This natural thinning is handy, because we don't have to worry about citrus trees over-producing and breaking the branches. Other fruit trees such as peaches and plums often set far more fruit than they 'should' and end up collapsing unless fruit is removed early in the season.

Why do my stone fruits have hardly any fruit this year?

We had 14 days of rain during the bloom period. Bees are finicky. High moisture caused fungus to blight the petals of apricots and plums. It's just been a tough year overall for fruit trees.

Figs are spoiling as they ripen: ok on the outside, yucky on the inside.

Figs set two crops in our area: the breba (spring) crop, and the fall crop. Figs are very soft and vulnerable to rot organisms if moisture is high, and this year we had over an inch of rain in the last week of June, which was very bad timing for the ripening breba crop. Hail damage in June allowed rot to set in. The fall crop, which is better and larger and arrives during reliably dry weather, should be fine.

Something is eating all the plums off my tree before they ripen!

Something is eating my young melons as they ripen!

Something is eating my oranges!

Management of tree rats and tree squirrels is very challenging. They move rapidly through the garden, damaging specific crops, and then move on. Basic animal management strategies usually involve:

removing habitat;

installing barriers;

applying repellents;

baits and traps.

Think like a rat. You are jumpy, want to keep moving and get some food without taking too much time about it because when you are out in the open you are vulnerable to predators. Prune to make the area more open. Slow them down with netting over and around the crop. Make noise somehow (wind chimes in the trees?). They may just go to your neighbor's yard.

One possible solution: a customer suggested sandwich bags to keep rats/squirrels away from pomegranates. You slip the developing fruit into a #4 sandwich bag and staple it closed.

In the landscape:

Newly seeded lawn areas suddenly died out after the rain in early June.

Seedling fungus diseases cause rapid die-off in warm weather, which is one of the reasons we get better results re-seeding lawns in the fall when nights are cooler and fungus isn't active. Rake out the area and add some more seed when weather cools off.

Problems with a redwood tree (Sequoia sempervirens): needles browning and dropping; needles scorched on surface; needles gray in appearance; no new growth.

Coast redwood needles

Most problems with Sequoia are related to watering. It is usually a problem with duration (not long enough), frequency (too often), or distribution (not enough emitters or sprinklers).
In this case, the tree was being watered with bubblers spaced at intervals around the drip line, PVC pipe with holes was installed vertically to promote deep watering. The bubblers were near the pipes so water flowed rapidly down. No spray or surface drippers.

It is normal for the older needles of coast redwood to turn brown and drop in late spring and more lightly throughout the year. The scorched needles and lack of new growth are signs that the tree is not happy. Here the problem wasn't lack of water, it was the distribution. Redwoods have many surface roots, so water needs to be distributed across the surface under the tree. Adding some mini-sprinklers to the system, or occasionally setting a sprinkler to augment the system, should restore the vigor.

Redwoods are never drought-tolerant trees, preferring evenly-distributed water every week or so throughout the summer.

Curled, distorted leaves on bay laurel.

A psyllid insect arrived in California's Bay Area a decade or so ago, and sometimes shows up here in the Valley. It is an aphid-like insect that sucks the leaves, and the leaf edges curl around it. If you carefully unroll the leaf edge you will find the culprits. Psyllids only harm the new growth, for a rather short period in the spring, and the damage is cosmetic. Bay trees that are pruned lightly are less affected, as the psyllid can't damage thicker mature leaves. Prune bay laurel seasonally for size control, if at all, and avoid shearing them.

My neighbor has planted "horsetail bamboo" and it is spreading into my yard. Can I sue him?

You can sue anybody. The question is whether you would prevail in court. Most judges aren't horticultural experts. I can tell you that horsetail (Equisetum species) is very invasive. It is NOT a bamboo, but has a growth habit similar to running bamboos: rhizomes spread quickly through moist soil into nearby beds and lawns. Herbicides won't kill it. Digging it out is difficult because it breaks and resprouts. A rhizome barrier will contain it until it goes over or under; barriers for spreading plants must be monitored seasonally.

People like the look of horsetail as an accent plant. Offer to buy your neighbor an ornamental grass, a phormium, or iris, and help to dig out the offending invader. In extreme cases a physical barrier (sold by bamboo supply specialists) and heavy-duty landscape fabric can hold it back.

General and wacky:

Do you have a product to control frogs? They're keeping me awake at night.

A set of earplugs is less than $10.

How do I kill the bees that are all around my shrub?

Don't kill bees!

What happened to all the ants?!?

They drowned. At least, that is my assumption. We normally get lots of questions about how to control ants as summer begins. This year, hardly any. The soil was saturated in December, again in March, and cold rainy weather continued into May and June.

They'll be back. Trust me on this.

What is the deal with olives? Fruitless? Sterile? Huh? I want one that won't make a mess.

There are self-sterile olives which can be cross-pollinated by other varieties, but which consequently set much smaller crops than self-fertile types. Olive pollen is very tiny, light, and wind-blown for a mile or more. So it isn't unusual for a “fruitless” type to set some crops of fruit. One variety called Swan Hill is self-sterile for both male and female flowers, so it is incapable of setting fruit. The patent on that variety has finally worn off, so it has become more readily available as other growers begin propagating it.

1. Why can't I find Scottish broom anywhere?

2. I was browsing your website and noticed that St. John's wort can't be sold in Yolo and was wondering why. I have some seeds of another Hypericum (punctatum) and want to know if I should worry about planting them or not, since it seems like a similar species.

Scotch broom (Cytisus scoparius) and St. Johnswort (Hypericum perforatum, aka Klamathweed) are both invasive species in the true sense of the word: non-native plants which reseed out into wild areas, displacing native vegetation, and possibly causing economic harm to farmland or rangeland. Scotch broom has become so familiar as an invasive that most wholesalers have stopped growing it; most have even stopped growing related broom species!

St. Johnswort is restricted from sale in Yolo County. Local agricultural commissioners have discretion about how they prevent the spread of invasive weeds that are listed on the state's official list. Our ag commissioner has decided to prohibit retail sales of Klamathweed. The restriction is specific and does not apply to other species of Hypericum.

A cautionary note:

A customer walked in waving a pest sample on a branch from an apple tree, from the Bay Area. Oh, my. We are in a quarantine district for Light Brown Apple Moth (LBAM), which is fully established in the Bay Area. There have been a few finds in Yolo County, though not in nurseries. Thank goodness. According to nursery folks in the Bay Area, a find prompts closure of the nursery, the whole place has to be sprayed, and then re-inspection is required before they can re-open.

Please don't bring plant materials into Yolo County from anywhere in the Bay Area other than from nurseries that have been certified as free of LBAM. Nothing from Aunt Minnie's backyard, please! That is how pests spread.

For more information about Light Brown Apple Moth, visit the state agriculture department web site: www.cdfa.ca.gov/LBAM

2011-07-16T22:36:00.000-07:00

Hi Don,

I was browsing your website and noticed that St. John's wort can't be sold in Yolo and was wondering why. I have some seeds of another Hypericum (punctatum) and want to know if I should worry about planting them or not, since it seems like a similar species.

Thanks!

H. perforatum is considered a noxious weed threatening rangeland in California, and sale in Yolo County is forbidden by the County Agricultural Commissioner. Management of weeds in that category is at the discretion of each county's ag commissioner, so other counties may allow them. You are not restricted from growing a different species; there are many other species of Hypericum that can be sold (and are not considered invasive). For example, H. perforatum and H. canariense are on the invasive plants database. Your species is not.
Here is a reference link: cal-ipc.org

Here is an article about true invasives and mere garden thug
Don

Common Landscape Errors

2011-06-21T13:01:00.000-07:00

or ... It Isn't The Plant's Fault!

Written for the Davis Enterprise, June 23, 2011

Many landscape problems arise from the lack of nexus between landscape designers and landscape managers. In other words, it is the wrong plant, installed incorrectly, or managed improperly. If it's too big, someone is going to want to prune it. If it is in the lawn, they'll want to (appropriately) keep the grass away. If it isn't standing upright, they'll want to pull it up straight.
Here are some of the most common errors I see.
(For an illustrated version of this article, click here)

Mulch too close to the tree.

Mulch is very beneficial to the soil, but needs to be applied carefully. Moisture trapped around the bark of a tree or shrub leads to infection by Phytophthora. The result is crown rot: sudden death of the plant in hot weather. This disease requires warm, moist conditions to infect a plant. Mulch should always be several inches away from the trunk of any woody plant, especially in the summer.

Watering too often.

The single most common landscape mistake: watering too often, and not deeply enough. See crown rot, above. Constant moisture around the crown of a plant leads to attack by rot organisms. You can't just set the sprinkler timer and fail to adjust it for changing weather patterns. Water as slowly, deeply, and infrequently as possible.

Almost nothing needs water daily. The only exception might be plants that are rootbound in containers, and newly planted seedlings for the first week or so.

Staking too close, too tight, and too long.

Trees need to move in the breeze in order for their trunks to strengthen. They should not bang into the stakes. Usually we use two lodgepole stakes, pounded securely into the ground several inches east and west of the trunk (because our prevailing winds are from the north and south). A flexible tie is used in a figure-8 pattern, on each stake, at the point of the bend. The patented Redi-Stake™ is a single-stake technique that is used by the city and some arborists. This metal pole and rubber -tie system holds the tree securely and safely.

As soon as the tree can stand upright, the stakes should be removed, usually within one growing season. Ties should be checked monthly. Materials that could cut into the bark, such as wire, should not be used for tying up trees.

Wrong pruning tools.

Young men, hear me! Hatchets and axes are not pruning tools! Chain saws should only be used by trained professionals. Hedge shears are specialized tools used only for removing tender new growth.

Use a pruning saw or loppers. Pruning cuts should be clean to allow prompt development of callus as the tree naturally covers the wound. Ragged cuts invite pest and disease problems.

Note: pruning paint is no longer recommended to cover pruning wounds. The black paints absorb heat and increase damage. Whitewash on newly-exposed bark may be appropriate in some cases. Most often we simply let the wound heal naturally.

Topping trees.

Size control of trees might be necessary if a tree is planted under wires or overhangs, in which case poor tree selection is the issue. Public utilities must clear branches from wires, and do so with little consideration for the health or appearance of the tree. Our local utilities, PG&E and SMUD, have excellent resources available for choosing trees to plant under their wires.

If a tree must be kept lower than its natural size, proper training when it is young can be done to select permanent branches that have safe angles and good position along the trunk. Shortening a tree that is already too tall can be done by licensed, certified arborists who will "drop-crotch" the tree, cutting taller branches down to a point where an existing branch is already growing.

Plant professionals will not lop off ("top") all the growth above a certain point, as it results in rank, poorly-attached limbs that become unsafe. If someone proposes this for your trees, get a second opinion.

Wrong plant, wrong place.

Surface roots

Surface roots are part of the genetic makeup of certain species. Riparian trees that naturally would grow along streams and rivers have shallow roots that rapidly colonize newly deposited soil after floods. Willows, poplars, cottonwoods, and alders are unsuitable landscape trees because of their extensive, aggressive roots. White birches can be a problem in lawns, though the surface roots may be acceptable in landscaped, mulched areas.

Other species may develop surface roots if they are watered shallowly, but less so if watered deeply and infrequently. Evergreen magnolias and Chinese tallow trees are examples. Even sycamores and plane trees can develop surface roots if a constant shallow moisture source is available.

Shrubs under windows

I don't really understand why 10-foot-tall shrubs are planted under windows. There are plenty of low-growing shrubs to choose from. The most common mis-used shrub in this category is Photinia Fraseri, the red-tip shrub that is ubiquitous in California landscapes. A lovely large shrub in its place, it is often misplaced under windows and has to be pruned monthly. Then it looks ugly, and often slowly dies out.

Locally invasive plants, not confined.
Running species of bamboo, mint, ivy, creeping fig (among many others): each may be appropriate in a particular place, in a pot, or with appropriate barriers, but can take over a yard if not constrained. Choose a clumping bamboo; plant your mint in a nice pot; choose another species of vine. Save yourself and the future owner of your yard a lot of trouble.

Misapplication of herbicides.

The results can range from annoying to heart-breaking. Glyphosate sprayed around dormant roses has severely harmed many a rose garden. "Weed and Feed" applied to the lawn can be taken up by roots of nearby trees; the most common damage is to birches, magnolias, and maples. Continual use of pre-emergent herbicides in non-turf areas can lead to anemia as roots are damaged over time. Weed-killers have consequences. Read and follow label directions, and use as little as possible.

Continued use of plants with known pest problems.

Here are three categories.

Trees and shrubs that will die or be disfigured and for which there is no practical remedy. White alder. Leylandi cypress. The pests and diseases that kill them have been known in the horticulture industry for decades. There is really no excuse for the continued sale of these species.

Trees and shrubs with annoying pest problems that don't affect the vigor or health of the tree. Two examples. Honeylocust trees are infested by a gall-forming midge that causes most of the leaflets to drop off from late spring through mid-summer. They grow fine but get sparse and have lots of litter, so they are no longer recommended. Photinia Fraseri gets lacebug in the summer which makes the leaves ugly. It is manageable, but there are many resistant hedge species available.

Plants which will require regular spraying throughout the growing season to prevent damage.

Common garden geraniums, petunias and their calibrachoa cousins (Million Bells TM, etc.), get geranium budworm throughout the summer here. The caterpillar eats flower buds and leaves, and needs to be sprayed every few days throughout the bloom season. Most people aren't willing to do regular spraying in their gardens in order to keep flower blooming. Why not just plant something else?

Indeed: why not plant something else? There are hundreds of plant species to choose from, with low-maintenance options for most situations. With professional advice, you can start with a plant that won't require follow-up care. Watered correctly, it will thrive. Treat plants with respect and they will reward you!

Tree resources from PG&E

© 2011 Don Shor, Redwood Barn Nursery, Inc., 1607 Fifth Street, Davis, Ca 95616

www.redwoodbarn.com

Feel free to copy and distribute this article with attribution to this author.

If April showers bring May flowers, what do May showers bring?

2011-05-29T15:22:00.000-07:00

Written for the Davis Enterprise, May 26, 2011
Click on any image for a larger version

Fungus!

Last May I wrote a column which began,

"What's up with this weather? ....
Below average temperatures every month ... by as much as 10 to 15 degrees. If we complete May without breaking 90 degrees, it will be the first time since 1971. Pleasant as that may be for gardeners, the weekly rain and cool temperatures have played havoc with plants and crops."

Well, deja vu.
For the record, we did finish May 2010 without breaking 90 degrees. So far this year, other than a brief spate of windy, dry, warm weather May 3 through 5, temperatures have been below average as well. Mild temperatures and high humidity lead to disease problems, and rain in March left many fruit trees nearly fruitless.

So we get questions ...
There are dead branches on my apple tree!

Fireblight on an apple tree.

Fireblight is a bacterial disease that attacks blossoms, young fruit, and tender shoots of apples, pears, and related trees and shrubs. It is specific to members of the pome branch of the rose family. Ornamental pears and crabapples, loquats and pyracantha can also be affected. Symptoms are rapid dieback of short shoot. The affected parts look burnt, as if by fire.

Fireblight infects within a temperature range of about 55 to 80 degrees and very high humidity, so normal hot dry weather stops the spread. But it can do a lot of damage in a short period of time. Prune out affected portions, cutting down into healthy green wood, and throw away the prunings. Contrary to older advice, it is not necessary to clean your pruning shears between cuts. The disease is transmitted by bees, and by spores during periods of very high humidity.

The tomato plant I bought a couple of weeks ago is not looking good. It is losing leaves and has black spots on most leaves (fungus?). I would think it is the cool weather and especially that crazy hail we had. The top part of the plant looks okay. Will it heal itself, or should I buy a new plant?

Early blight is a leaf-infecting fungus on tomato seedlings. It was most likely on the plant when you bought it. Normally we don't have to worry about it here, because the fungus can't sustain low humidity. Cold temperatures have slowed the growth of the seedling, hail has made points of entry on the leaves, and rain has continued to splash the fungus upward. It will likely outgrow the problem.

Why is there hardly any fruit on my apricot, plum, peach, or nectarine?

European honeybees are finicky workers. They won't fly when the weather is cold, windy, overcast or rainy. We had 14 days of rain in March when the stone fruits were flowering. So some varieties got good pollination, but most didn't.
Apricots were hard hit by brown rot fungus again this year. The disease attacks and kills blossoms and developing fruit, sometimes spreading into the branch. Plums, and peaches and nectarines, also show dieback and fruit loss due to brown rot. Prune out the dead twigs as best you can, and mark your calendar to do a dormant spray next winter. Brown rot is the major factor limiting success with apricots here.

What is causing the holes on ...

... the leaves of my plum and pluot?

Shot hole fungus on a plum

Shothole fungus causes small areas of the leaf to die, and then the dead tissue falls out, leaving a small hole. It looks as though something has been eating the leaf. Not very harmful, but it does increase over time. The dormant spray noted above will help prevent it.

... the petals of my roses?

Earwigs like to crawl up rose bushes and feed on the thrips that are hiding among the rose petals. That is helpful, but unfortunately they also like to eat rose petals. Earwigs can be trapped with any fragrant cooking oil, left out in shallow bowls.

Katydids have just hatched out, and can be found here and there feeding on soft green leaves and rose petals. Their damage is transitory, and they move on quickly, so control is not necessary (or feasible).

What is causing the spots on the leaves of (1) my citrus; (2) my persimmon?

Spots on persimmon caused by environmental stress.

If you want to impress people, tell them the leaves have oedema. That is Greek for "spots." On thick-leaved plants oedema occurs during conditions of high or low temperatures, low humidity, and wind, It is an environmental stress and is not harmful to the tree. In the summer oedema can make Eastern redbud leaves (Cercis canadensis) unattractive.

Why are the flower buds of my gardenia falling off without opening?
Cool weather. Gardenia wants even, warm temperatures all the time. The plants will initiate flower buds at any time of year, but if the nights are cooler than about 55 degrees the buds will drop without opening.

If I plant hot peppers near my sweet peppers, will it make my sweet peppers hot? or vice versa?
If I plant a lemon near my orange, will it make my orange sour?
No, and no. The only time cross-pollination in the garden affects the part of the plant that you eat is when you are eating the seeds. So certain types of corn need to be isolated from each other, because you are eating the seed; never plant sweet corn near field corn or popcorn, or many of the kernels will be very chewy!
Oranges may be sour because the tree isn't getting enough sun. More commonly it is because you are harvesting too early. Many citrus turn color before they turn sweet.
The heat in peppers is caused by capsaicin, which is present in varying quantities in hot peppers and not present in sweet peppers. Hot peppers vary in their heat due to genetics (the type and seed strain of the pepper), environment (hotter in hot climates), and watering (reducing water concentrates the flavor, including the heat). Most of the hot pepper varieties we grow are open-pollinated seed strains, so their genes are more variable than hybrids. If your "sweet" pepper turned out to be hot, it was mislabeled. If your hot peppers aren't hot enough, try watering less.

Cross-pollination in the garden can affect the seed you save. If you carefully save seed from your favorite squash plant, but had a pumpkin nearby, you can get some very strange results in the next generation.

What are these dragon-looking bugs on my salvia?!?
Those are the larvae of ladybird beetles, aka ladybugs. The larvae eat aphids even more voraciously than their parents. You will also find an intermediate stage between the larva and the adult. Other beneficial aphid-eaters in the garden right now include leatherwing beetles and the larvae of lacewings. It is rare for us to need to spray for aphids once we have a resident population of beneficial insects. Sprays often kill the beneficials. So let nature run its course, and learn to recognize the good bugs.

Ladybird beetle (ladybug) larva.

Ladybird beetle pupa

Ladybird beetle adult

All the stages!

© 2010 Don Shor, Redwood Barn Nursery, Inc., 1607 Fifth Street, Davis, Ca 95616

www.redwoodbarn.com

Feel free to copy and distribute this article with attribution to this author.

Lavenders!

2011-05-04T23:26:00.000-07:00

What's that purple flower?!?

(Click on any image for a larger version)

You'd be surprised how often I get that question. In winter, it's rosemary or lilac vine (Hardenbergia). In spring, California lilac (Ceanothus) blooming in the Arboretum draws admiring visitors and bees. Thanks to the City of Davis, some of our roadsides have low-growing shrubs with vivid purple flowers right now: Spanish lavender (Lavandula stoechas Otto Quast).

Lavandula stoechas 'Otto Quast' in mid-street planting

Otto Quast is one of the Arboretum All-Stars, and for good reason. Lavenders in general are tough, drought-tolerant shrubs. What sets Spanish lavender apart is that it blooms early, often starting in February and continuing into the summer. The shrub has a low spreading habit.

Unlike other lavenders, it also has a set of showy petals atop the bloom spike. These act as a 'come hither' for pollinators, so Spanish lavender is less fragrant than other species. Breeders have introduced new forms with stronger or softer colors and some have even longer petals than Otto Quast, which will probably supercede it in the nursery trade.

What do lavenders want?

Lavenders are from the Mediterranean, so they are perfectly adapted to our climate of hot sunny days and dry summers. Growers in areas with summer rainfall struggle to keep them alive because of their sensitivity to crown rot. Commercial lavender production has been tried in many parts of the U.S., and the limiting factors are winter cold and high summer humidity, neither of which is an issue here.

Lavender farmers are advised to take extensive measures to improve soil drainage. From one publication: “Beds must be worked down 18 to 24 inches. It is best to raise the bed about 6 inches above ground level and mix in 1/3 sand, 1/3 loam, and 1/3 clay soil.” [ATTRA*]

A mixed bed of lavenders in June. The English lavenders are in full bloom, and the lavandins (hybrid lavenders) are just beginning to spike. Blooms will continue through the summer, even into the fall. Lavender plants like full sun and dry soil.

Well, folks, add one more advantage to living in California. We don't have to do any of that to grow lavender here. Just plant the shrubs elevated so water never stands around the stem: a raised bed is fine, but a slight mound or furrow is fine. Water should drain away from the plant. Water every few days to get the plants established. Then lavenders can be irrigated deeply and very infrequently.

I water my mixed lavender planting every 3 to 4 weeks with a drip irrigation system that runs for several hours or overnight. Established plants can survive the summer without any watering, though that may truncate the bloom season. In any case, never water them more than once a week unless they are in containers.

Gardeners get perplexed about what to do with lavender shrubs after a few years. The nature of the plant is that it sprawls and tends to lose foliage in the center. Light trimming with shears after bloom can encourage a bushier growth habit. Or you can just let them slowly fall apart, try cutting them back hard after a few years (sometimes this kills the shrub), or simply replace them. A new plant will bloom in the second year; often in the first.

In sum: lavenders love sun, tolerate extreme heat and wind, and prefer dry soil. There are a lot of different kinds!

Which smell best?

Traditional lavender for sachets and potpourri is English lavender (L. angustifolia). Hybrids between English and Portuguese lavender (Lavandula spicata) are called lavandins, and they are the oil producers. (Just for the record, English lavender is not native to England; it came from northern Spain.)

There are several chemicals in lavender flowers that make up the aroma, and the exact constituents vary between species, as well as what part of the plant contains the most of each. Portuguese lavender contains more camphor than English does. Some varieties have aroma compounds in the leaves, others in the flowers. French lavender has especially fragrant leaves.

The English flowers are sweeter, the others more acrid but with longer-lasting scent. So lavender products often contain both. Spanish lavender smells slightly sharp, sort of like turpentine, but the oil is used in air fresheners and insecticides.

Which look best?

Most have grey-green leaves. Some are nearly silver, and a few are variegated. French lavender has toothed leaves (dentate), and the Arboretum All-Star hybrid called Goodwin Creek inherited those. A number of varieties are more compact growers, making them better for small gardens.

When do they bloom?

English and hybrid lavenders start blooming later than Spanish does, mostly beginning in May. Lavandins bloom for much longer than most references describe, making them some of our best garden choices. I have found these often continue blooming into the fall.

A gallery of lavenders

click to enlarge

Lavandula stoechas
'Dedication'

Lavandula stoechas 'Passione'

Lavandula officinalisEnglish lavender bloom spike

Lavandula pinnata

Lavandula x 'Grosso'

Lavandula 'Warburton'
has variegated, fragrant foliage

Bees love lavender flowers!

Here is a summary of the types,

including just a few of the many varieties available in nurseries:

Lavandula angustifolia ENGLISH LAVENDER

Bloom earlier than Lavandins; shorter spikes, darker flowers. The strongest sweet lavender fragrance. Very seasonal bloom (May - June here), and they often don't flower heavily until established.

o Hidcote Compact, very tight growth to 1-2 feet tall and wide, with darkest purple blue buds and flowers. Foliage varies from green to very gray.

o Lavender Lady Similar to Munstead, this seed-grown strain blooms the first year. The only lavender available in six-packs.

o Munstead-To 2 feet tall, spreading, with light purple flowers. Foliage usually green, but may be gray-green.

Lavandula dentata FRENCH LAVENDER

Big 4 x 6 shrub with green, toothed leaves (there is a gray version, L. dentata candicans) Showy purple flowers spring through fall. Foliage is fragrant but flowers aren't. Not common in the trade. Notable as a parent of the Arboretum All-Star:

o _L. x 'Goodwin Creek' -- 3 x 4 shrub with soft, densely woolly gray green leaves with coarsely serrate margins. Grown for great, gray leaves and attractive habit, with a continuous display of very dark purple flowers in spring, summer, and fall. Medicinal scent.

L. x intermedia LAVANDIN

Bloom later than English lavenders; longer flower spikes, fatter flowers. Originally grown for lavender oil. Later cultivars were selected for showiness. Flowers June through summer here, often into fall.

o du Provence To 3 feet tall, spreading wider, with lots of flowers over a long season. Very fragrant, very popular garden variety.

o Dutch Mill To 2 feet tall, 3 feet wide, with flower stalks to 18-24 inches long. Rich deep purple flowers are extremely fragrant.

o Grosso Compact growth with thick spikes of dark purple buds and purple flowers. Commercially grown for oil. Very fragrant. One of the best.

o Twickel Purple More violet-purple than Grosso. Very fragrant. Sometimes listed as a form of English lavender.

Two more are worth mentioning for their extraordinarily long bloom season, and frost tenderness. Often sold alongside hardy types, leading to consternation when winter arrives and they may be killed. Flower spikes are great for cutting, though they aren't fragrant. Worth growing for the abundance of bloom and intensity of color.

o L. multifida FERNLEAF LAVENDER

2 x 3 shrub with soft, ferny green foliage. Blue-violet flowers. Always in bloom. Tender; grown as annual here.

o L. pinnata buchii

3 to 4 feet tall and wide with feathery gray-green leaves and stalks of dark purple flowers which open spirally along the cluster through the summer. Tops are frozen back at 25 degrees; usually grown as annual here.

References:
*National Sustainable Agriculture Information Service, ATTRA

For more information about the Arboretum All-Stars, visit their website, and see our Davis Enterprise article from December 2009.

Written for the Davis Enterprise, April 28, 2011

© 2010 Don Shor, Redwood Barn Nursery, Inc., 1607 Fifth Street, Davis, Ca 95616

www.redwoodbarn.com

Feel free to copy and distribute this article with attribution to this author.

Easy Edibles!

2011-03-30T22:28:00.000-07:00

Written for the Davis Enterprise, March 24, 2011

Click on any image for a larger version

We get questions.

I have never planted a living thing before. I have a patio and I want to plant some edible things.
Which fruit trees do you have to spray for bugs?

There are lots of new gardeners these days planting fruit trees and vegetables. Many express concern about the amount of time or expertise they'll need. Bottom line: many of you want to grow food without fuss.

My definition of easy: a plant that gives good food without any special fuss! No routine spraying needed. Simple pruning, if at all. Tolerant of a range of soil and water conditions. Here are a dozen or so easy edibles.

1. Strawberries

Garden strawberry (Fragaria chiloensis)

Easy? They flower within weeks of planting and set fruit right away.

Grow strawberries in half or full-day sun, in soil that you've added compost to, and where you can water them frequently. Plant Sequoia for best flavor, day-neutral varieties to extend the season.

Hint: Protect the fruit! Spread coarse bark around the plants just as they begin to flower. They'll set their fruit above the ground, away from sowbugs and slugs. Plants live 2 - 3 years.

Alpine strawberry (Fragaria vesca) is very different. The plants do not produce runners; great for the herb garden or even in pots. Produce small very sweet berries throughout the summer.
Prefer some shade. Plants live many years.

2. Some easy Citrus

Kumquat (Fortunella species)

The hardiest citrus. Full sun or light shade. Not fussy about soil, but like regular feeding.

Peel is sweet, flesh is tart. Ripen year-around. Fragrant flowers in summer.

Nagami has bright orange fruit shaped like an olive. Very ornamental; best-known type. Meiwa has sweet, round fruit.

Hybrid kumquats gain some cold-hardiness from the kumquat parentage. Calamondin is a prolific producer of round, tart fruit that are used in drinks and as garnish. Limequat is hardier than lime, but has similar flavor.

Lemons (Citrus x limon)

Full sun or light shade. Somewhat frost tender, especially when young.

Meyer Lemon is said to be a cross between a lemon and a mandarin. Compact plant to about six feet, easily kept lower. Can flower, set, and ripen fruit year-around.

True lemons (Lisbon and Eureka varieties) grow much larger and have thorns.

Mandarins (Citrus unshiu)

Full sun for best flavor. More cold-hardy than other citrus.

Owari Satsuma is the hardiest, best-known mandarin, ripening November - January. Other varieties extend the harvest season through spring. See our article on mandarins from December 2010.

Oranges (Citrus sinensis)

Full sun for best flavor. Young plants may need frost protection; established trees survive cold weather.
Navel and blood oranges ripen in winter. Other varieties ripen in spring. Valencia oranges, used mostly for juice, ripen in spring and summer.

3. Mediterranean and Asian fruits

Figs (Ficus carica)

Tolerant of nearly any soil. Can live without any summer watering; very heat tolerant. Produce a small crop in spring and a large crop over several weeks in late summer and fall. The sheer quantity of fruit can be a problem.

Black Mission and Brown Turkey are the common backyard varieties. Gourmet figs also do well: white (Conadria, Kadota), striped ones (Panache), and more. Slow-growing variety called Blackjack can be kept under 10 feet.

Mulberries

Easy? Indestructible.

Morus alba is the white mulberry. The fruitless male is used as a huge shade tree. Teas Weeping is a fruiting type easily kept below 10 feet tall; cute garden accent or playhouse for young kids, with mild, sweet fruit that stains everything. Reseeds.

Morus nigra is the black mulberry, including Russian, Persian, and Pakistani varieties. Slow-growing small trees to fifteen feet, easily kept lower. Large, soft, juicy, intensely sweet-tart fruit resemble giant blackberries. Birds love them. Fruit stains fingers, sidewalks, and clothing. Does not reseed.

Persimmons (Diospyros kaki)

Tolerate drought or garden watering. Beautiful chartreuse foliage in spring; showy fruit in winter. Grow at moderate rate to thirty feet by twenty feet, but can be pruned for size. Produce dozens to hundreds of fruit. The trees drop fruit steadily all season, including lots of unripe fruit as the tree thins itself. Birds will enjoy what you don't harvest.

Fuyu is the flat-bottomed variety you eat while it is still firm. Hachiya has elongated shape and is puckery-astringent until squishy-soft.

Pomegranates (Punica granatum)

Probably the most heat and drought tolerant fruit species. Showy red flowers in late spring; nice yellow fall color, then bright red fruit in fall and winter. Attractive large shrub can be trained as a small tree.

Look for Wonderful, Granada (earlier-ripening), Angel Red (more juice. A number of other varieties are becoming available.

4. Plums

Many stone fruits need careful pruning and spraying. Plums are nearly foolproof. Take partial shade or full sun, average watering.

Japanese plums (Prunus salicina)

Tangy-sweet flavor. These listed are self-fruitful, meaning you only need one tree. Good thing: they're very productive. Santa Rosa produces prodigious quantities of fruit (hundreds) that ripen all at once. Emerald Beaut, Howard Miracle, and Nubiana have fruit that hangs on the tree for a couple to several weeks, remaining firm and of good quality.

European plums (Prunus domestica)

Maybe if we stopped calling these "prune plums" more people would grow them. The fruit, fresh off the tree, is firm and very sweet.

5. Guava-like fruit

Chilean guava (Ugni molinae) and Pineapple guava (Feijoa sellowiana, now Acca sellowiana) are hardy ornamental shrubs with edible fruit (and edible flowers in the case of Feijoa).
Tolerant of sun or light shade, and drought.

6. Some easy vegetables

Anyone gardening with kids should plant radishes and sunflowers; quick to sprout, easy to grow. Full sun.

Gypsy pepper is the most productive sweet pepper I grow. Each plant produces at least a dozen pale yellow-green fruit which ripen red very quickly.

Small-fruited tomatoes are reliable, heavy producers. Choose Juliet hybrid, Sungold hybrid, or two popular heirlooms: Currant, and Yellow Pear.

Finally, kitchen herbs are very easy to grow in the ground or in containers, an excellent choice for novice gardeners. Mix several types in a container, preferably in at least part-day sun (full is best).

Some are long-lived garden perennials or shrubs, while others are annuals. Basil is in the latter category. If you are limited for space, plant Spicy Globe bush basil, a compact one-foot plant with extra-pungent leaves.

7. Also-rans

My Davis Enterprise columns are supposed to be 1000 words. That is a good thing, as it keeps me focused and makes me assess my criteria more carefully. Here were the ones that ended up on the cutting-room floor.

Pie Cherries

Bright red, pretty fruit on very productive, ornamental little trees. Rich flavor. All are self-fruitful and ripen later than sweet cherries, perhaps avoiding the main infestation period of the Spotted wing drosophila. Until we know better how much of a problem that pest will be, these are 'provisionally' easy.

Varieties:

English Morello

Blood-red juice, red flesh, bright red skin, very tart pie cherry. Late June, early July.

Montmorency

Clear juice, white flesh, bright red skin, less acidic pie cherry. Mid to late June.
Hint: long ripening period.

Jujubes (Zizyphus jojoba)

Pretty little trees with shiny foliage are very tough, easy to grow. Produce loads of fruit in early fall that look like little elongated brown apples. Sweet as dates when dried.

Quince (Cydonia oblonga)

Tolerant of heavy soil, lawn watering, or drought. Trees, often multi-trunked, grow to ten feet or more.

Smyrna Quince is the best-known variety, with several dozen very hard, lemon yellow fruit that have rich perfume and wonderful flavor, used in cooking and preserves. Ripen in fall.

Fragaria vesca

Alpine strawberry

'Nagami' kumquat

'Meyer' lemon

Navel orange

Black (Persian) mulberry fruit

'Hachiya' persimmon

'Santa Rosa' plum

Ugni molinae

Chilean guava

Feijoa sellowiana

Pineapple guava

'Juliet' tomato

'Sungold' tomato

A bowl of mixed basil

Top of Page

What's That Tree?

2011-02-23T17:15:00.000-08:00

Written for the Davis Enterprise, February 24, 2011

Click on any image for a larger version

Overheard at the UC Davis Arboretum, Feb. 20: "This is why I moved here from Michigan."

I was standing in the Eric E. Conn Acacia Grove, trying to get a close-up of the daffodil-yellow clusters of blooms. February is still technically winter, and we've had more than our share of dreary weather this season. But on a sparkling sunny February day recently, folks were outside enjoying the early flowers.

Acacia dealbata Silver wattle

Trees blooming in February? Of course. The almond blossoms began a week ago. Flowering pears a week before that, and flowering plums have already passed their peak of bloom. The earliest flowering cherries such as Okame are in flower. In the family orchard the first peaches have broken dormancy. Back in the arboretum, a little further down the path from the acacias, Western redbuds are showing bud color; expect blooms in a week or so.

Almond blossom in February

I am accustomed to getting inquiries about the early-blooming trees and shrubs. Folks who move here from real-winter climates can't seem to believe that this is normal. From the other end of the spectrum, folks like me who moved here from milder climates don't recognize them. Deciduous flowering trees and shrubs need a certain amount of winter chilling to break dormancy and flower properly. Coastal southern California doesn't get enough cold for that.

I do remember an old Acacia baileyana tree in our yard in San Diego; old by acacia standards, that is. Mostly subtropical trees or shrubs, fast-growing acacias tend to have weak wood and poor branch angles, so many fall apart after 20 years or so. I can't really recommend most species for residential landscapes, and nursery availability is very limited. Fast-growing, low-demand trees tend not to be popular with wholesalers; some may be available at arboretum sales. But the arboretum collection is a winter delight, and thanks to a donation from Dr. Conn there are now paths, benches, and signs identifying the species.

So what is blooming in February? More-or-less in order of bloom:

Flowering pear (Pyrus kawakami).

The first to bloom, these can be seen along F Street. In Southern California they are called Evergreen pears; down there, they get enough chilling to bloom, but don't drop their leaves in fall. Here they are usually deciduous. Drawbacks: odd flower odor; leaf-spot fungus, bacterial fireblight.

Almonds (Prunus amygdalus).

Almonds grow in a narrow climate range around the world, with California's Central Valley producing 80% of the world's supply. Commercial types get fifteen to twenty feet tall and broad, and two varieties are necessary for cross-pollination. The dwarf variety Garden Prince is self-fruitful and grows to about ten feet.
Almonds are not real fussy about soil. Water deeply every week or so during summer. Disease and pest problems are not significant.

Prunus blireiana Flowering plum

Flowering plums.

Prunus blireiana is first to bloom with semi-double soft pink flowers. Foliage emerges bronze-red, then turns dark green by summer. Fruitless. Prunus cerasifera varieties are next, and are popular for the purple-red foliage. Krauter Vesuvius has become the most widely-planted type because it is nearly fruitless. Older varieties had copious fruit.
Plums aren't fussy about soil, and can even tolerate lawn watering. Leaf color is more intense in full sun. Leaf-spot fungus and aphids can be a nuisance but are manageable.

Prunus 'Okame'

Flowering cherries

Most varieties bloom in March, but Okame (Prunus hybrid) is an early-flowering cherry with February blossoms. Ornamental cherries have diverse growth habits. This one is upright and round-headed.
Cherries are fussy about soil, requiring good drainage and at risk of crown rot if watered too often. Don't plant in the lawn!

Note: almonds, pears, plums, and cherries should have their trunks painted with an interior white latex paint at the time of planting to prevent sunburn and borers.

Magnolia?

Walking further to the west in the arboretum, past the Putah Creek Lodge and uphill toward the gazebo, I suddenly found a tulip tree in full bloom. Huh? Magnolia soulangeana blooms in early March, but this variety is ahead of schedule. Varieties range from dark to light pink, with other deciduous magnolias available that are pure white.
Magnolias are not drought tolerant, and the foliage can burn during extremely hot weather. The slow-growing trees reach ten to twenty feet or more tall with equal spread, depending on variety.

Prunus 'Okame'

Flowering quince

Chaenomeles japonica. A non-descript deciduous shrub the rest of the year, quince suddenly bursts into bloom as early as January with blossoms opening for several weeks. Varieties range from three to ten feet in height, usually with an angular spreading habit. Flowers are pink, red, or white; in the case of variety Toyo Nishiki, all three colors occur on the same plant. The shrub has a tight clump of multiple shoots rather than a single trunk. It can be planted and pruned as a hedge. Very tough, carefree, they are tolerant of any soil, sun or light shade, and either regular watering or drought. Some set hard apple-like fruit, which is very aromatic and makes wonderful jam.

Chaenomeles japonica

A few other notable February bloomers:

Chaenomeles japonica 'Toyo Nishiki'

Lilac vine
(Hardenbergia violacea 'Happy Wanderer'): vigorous vine to 15 feet or more with royal purple flowers in February. Full sun is best; partial shade o.k. Freezing weather nips the flower buds some years.

Oregon grape
(Berberis aquifolium, formerly Mahonia aquifolium). More yellow flowers in the arboretum. Note: yellow flowers attract beneficial insects. Oregon grape can be a scruffy-looking shrub, and the leaves are prickly. But the shiny foliage and early winter bloom, plus bird-attracting fruit, make it a good background shrub in a wilder landscape. It is tolerant of sun or shade, regular watering or considerable drought.

Winter daphne (Daphne odora 'Marginata')
Folks admire the specimens blooming right now in the Ruth Risdon Storer garden at the west end of the arboretum. There are also some pure white-flowered daphne nearby in the Shields garden. The fragrance of daphne is astonishing. Unfortunately, they are easy to kill, requiring perfect drainage and careful water management.

Dormant spray recommendations.

2011-01-15T11:38:00.000-08:00

Always read and follow label instructions!
For the products we sell, mix together in each gallon of spray:
2 oz LiquiCop (= 4 Tbsp)
2.5 – 3.5 oz spray oil
(= 5 – 7 Tbsp, or 1/8 to <1/4 cup)

You can use a hose-end sprayer** if you use the lower amount of oil (you will barely add any water to the concentrated mixture). Otherwise, use a tank sprayer.
Spray the tree thoroughly, to the point of runoff.
It will probably take about two gallons of spray to cover a medium-size tree with conventional training and pruning; one gallon of spray to cover a summer-pruned backyard orchard tree.
Spray peaches and nectarines while they are still dormant.
You can spray other fruit trees such as apricots. plums, and cherries with the same mixture.
Many fruit species such as figs, persimmons, and pomegranates need no spraying. Citrus are sprayed only as needed for specific pest and disease problems.
Dormant and bloom sprays don’t control the worms that get into apples and pears, or the new fruit-fly larvae that are attacking cherries. For those we use growing-season sprays.

The diseases we are concerned about are:
• peach leaf curl, which only affects peaches and nectarines. Sprays are only effective before the buds break. If they show color (green or pink) it is too late.
• brown rot, which primarily affects apricot (and almond) blossoms. See note*. Sprays are only effective when the trees are in bud and bloom. Plums and cherries, as well as peaches and nectarines, can also get brown rot, but it is much less common.
• This spray mixture also helps control shothole fungus, and the oil helps to reduce over-wintering insects.

Notes:
MicroCop (copper sulfate) and Polysul (lime sulfur) are no longer available, so we are now recommending the liquid copper spray. It is less effective for leaf curl, unfortunately, but easier to apply. The problem is that the final spray solution, following label rates, is lower concentration than you were applying before. We cannot recommend that you exceed the label rates.

** You cannot apply both products at the same time in a Dial-A-Pro hose-end sprayer. Apply each at the label rate, 24 hours apart.
* Copper is not effective for brown rot on apricots, and there is no organic or low-toxicity alternative available to homeowners. Chlorothalonil is available, but is very toxic; read and follow label instructions carefully if you choose to use it. Note non-chemical suggestions for control measures at ipm.ucdavis.edu:
Prompt removal and destruction of fruit mummies and diseased plant parts prevents the buildup of brown rot inoculum and helps keep rot below damaging levels. Prune trees to allow good ventilation. Furrow irrigate or use low-angle sprinklers to avoid wetting blossoms, foliage, and fruit. Plant varieties that are least susceptible.

Product information:

LiquiCop

Spray Oil

draft Jan 14 2011

Read and follow label instructions!

2011-01-11T11:56:00.000-08:00

Read and follow label instructions.
This is an important phrase! It affects the safety and effectiveness of the products you use. Failure to read and follow label instructions can injure or kill you or others, lead to plant burn, harm beneficial insects and wildlife.
What exactly does it mean? How do we intepret the labels on pesticides?

Signal Word.
Any pesticide, organic or otherwise, is labeled with one of the following words:
Caution
Warning
Danger
Those are in increasing levels of toxicity: Caution products are the lowest toxicity, Danger are the highest. The toxicity is based on direct harm the pesticide may cause by swallowing it, inhaling it, getting it on your skin, or getting it in your eyes. Tests are done to determine how lethal it is and how likely to cause skin or eye irritation.
Different products with the same active ingredient may have different Signal Words due to differing dilution rates of the concentrated or mixed solutions.

Precautionary Statements
These give you a guide as to what makes a particular pesticide dangerous to you or others. It may be swallowing or inhaling the pesticide, absorbing it through the skin or eyes, or direct irritation from contact with the concentrate or mixed spray.

Personal Protective Equipment (PPE):
The label will tell you which protective clothing or gear to wear, how long you, children and pets need to stay out of the treated area. Most people fail to heed this, but it is key to protecting yourself and others from harm.

Environmental Hazards
The label will state whether it is toxic to wildlife. Unfortunately, the impact on bees is not always mentioned. The likelihood of drift, runoff, leaching, and groundwater contamination may be mentioned. These are technical terms that you should understand before you apply the product.

Active ingredient
You may not recognize the name, because a chemical may be better known by its trade name. Example: Daconil is the trade name of chlorothalonil. Manufacturers do not have to disclose the inert ingredients, but do have to list their percentage.

California’s Prop 61 requirement:
If an ingredient in the product, active or otherwise, is “known to the state of California to cause cancer” that must be on the label. It's up to you as to whether that matters to you.

Storage and Disposal
There are general instructions for how to dispose of partially used or empty pesticide containers. Where do you keep your pesticides?

What if you lost the label?
Nearly every company now puts pdf copies of their product labels online. Hey, you can increase the font size and actually read it!

Do organic pest control products have the same labeling?
Yes. Anything that is sold as a pesticide in California has to be labeled. Organic pesticides aren’t necessarily safer than conventional ones.

Here is an example of a commonly used home garden fungicide:

Monterey brand FRUIT TREE, VEGETABLE & ORNAMENTAL FUNGICIDE
“Active ingredient: chlorothalonil 29.6%” You may know this as Daconil, a trade name.
“Known to the State of California to cause cancer.”
Signal Word: “Warning.” Red flag. This is one of the more toxic products homeowners can buy. I always urge purchase and use of a Caution labeled product if possible.

Precautionary Statements: “May be fatal if inhaled. Harmful if swallowed or absorbed through skin. Causes moderate eye irritation. Avoid contact with eyes, skin or clothing. Do not breathe spray mist. Prolonged or frequently repeated skin contact may cause allergic reaction in some individuals.”
Now we know where the Warning label comes from. Given these specific warnings and that higher-toxicity Signal Word, it is important to use the exact protective equipment listed.

PPE: The following are required: long-sleeved shirt, long pants, shoes and socks, protective eyewear, specific types of waterproof gloves, an approved respirator with an organic vapor cartridge or canister with a specific type of filter. You should not even open the bottle until you are wearing all of these listed items.
“Keep children and pets off treated area until dry.” The sprayed material on the leaves can poison them.

Environmental Hazards: Chlorothalonil can kill aquatic invertebrates and wildlife, can drift to nearby water, can runoff into surface water for “several days or weeks after application.” It can leach into groundwater, even when used according to the label.

Directions for Use: These give specific rates of application for certain pests on certain types of plants, by name. The rates are not the same for every crop. Do not exceed them, as they are based on tested effectiveness and are the basis for how toxic the product is considered to be. In some cases they will tell you a maximum amount you can use per year.
The Preharvest Interval (PHI) tells you how many days before harvest you can apply it. These vary by crop (14 days for onions, 7 days for cabbage, day of harvest for carrots), so you need to check the label carefully.
“Avoid spraying plants during extremely hot and sunny weather.” This is because chlorothalonil, like many pesticides, can burn the foliage during hot weather. “Do not apply … within one week … of oil or an oil-based pesticide.” Same issue: you may burn the leaves when used in combination with oil.

Storage and Disposal: These don’t vary much from one product to another, but it is wise to read them. In particular, disposal of the empty container has specific requirements. When you use the last of the bottle, rinse it three times and pour the rinse water into the spray tank. Then puncture the bottle (to prevent re-use) and dispose of it according to local regulations. If you don’t know what those are, contact your local agricultural commissioner.

For some discussion of a new product for vegetables and fruit trees, here is a previous blog article:
http://redwoodbarn.blogspot.com/2010/05/bayer-advanced-fruit-citrus-vegetable.html

In Memoriam: Dan Pratt

2011-01-05T21:24:00.000-08:00

I am sorry to report that Sacramento-area nurseryman and garden media personality Dan Pratt died December 25 at the age of 78. Pratt succumbed to injuries from a fall, after a series of illnesses over the last several months.

Employed by Capital Nursery for 24 years, he was heard locally on KFBK (originally KGNR) radio with his Garden Doctor program, which ran for 19 years: first from 9 to 11 a.m. on Saturdays, and then from 8 to 10 on Sunday mornings. For more than 20 years he wrote a weekly column about garden pests for the Sacramento Bee (What’s Bugging You?) and made frequent appearances on local television. His annual garden calendar was sold at garden centers throughout Northern California.

Pratt gave many talks over the years to garden clubs around the Sacramento Valley. He was active in the local chapter of the California Association of Nurseries and Garden Centers, serving as president twice and on the board of directors for several years. Dan led garden tours of Britain and other regions. After his retirement he moved back to his family’s property in Napa.
He leaves a son and daughter and longtime girlfriend. A private burial service has been held.

That all sounds very dry. I considered Dan a friend for over 25 years, having met him when I first got involved in our local chapter of the nursery association. He was always full of ideas, present at nearly every nursery event we worked on, and enthusiastically promoted gardening and the nursery industry. Dan introduced me to radio work and graciously allowed me to host his show when he traveled. After retirement, he and Jo stopped by my shop any time they were passing by Davis, to swap stories and tell jokes. He liked good food, cruises, and terrible puns.

Dan Pratt was a great friend of gardens, gardeners, and garden centers everywhere.

Addendum: from the Sacramento Bee Jan 7 2011

Mandarins!

2010-12-24T11:40:00.000-08:00

Satsumas and other mandarins

Written for the Davis Enterprise, December 23, 2010

Click on any image for a larger version

We get questions, this one from Davis Enterprise columnist Dan Kennedy:
Please tell me about satsumas and the other types of mandarins: what they are, which are best here, why a frost improves the flavor, and how to grow them.
Dan's recent column [Satsumas, the sweetest citrus, Dec. 8 2010, Davis Enterprise, available to subscribers at their web site] focused on the buying and eating part, and touched on how to grow them. But questions about citrus always seem to beget more questions, as they are a complex group of fruit trees.
Mandarin oranges are a sign of the holiday season in California. In my Southern California childhood it was a Dancy tangerine that filled the toe of the Christmas stocking. We'd spit the seeds at each other out on the dichondra lawn as we waited for the grownups to waken. Dancy is a rich-flavored, juicy, seedy, easy-to-peel type of mandarin orange (tangerine and mandarin are interchangeable terms) that ripens in time to market for the holidays.

What exactly are these Satsuma mandarins we grow?

Satsuma is a generic term for a number of different varieties of (mostly) seedless, easy-to-peel mandarin oranges. The UC Riverside Citrus Variety Collection site lists over a hundred different clonal lines called mandarins, representing a couple of dozen species, numerous hybrids, and many bud sports. Of those, over three dozen from various sources are called Satsumas. Owari Satsuma is the best known, and the classic reference The Citrus Industry (1967) describes Owari as "of ancient and unknown Japanese origin presumably from the old province of Owari, whence the name."
Most common in California is a variant called Frost Owari. H. B. Frost was a researcher at the UC Riverside Citrus Station in the early 1900's. The name has nothing to do with cold-hardiness. (There is also a Frost Lisbon lemon and a Frost Marsh grapefruit, named in honor of Frost's work at developing nucellar seedling clones. That's a whole 'nother column.)

'Owari Satsuma' mandarin

Satsuma, a name we apply to popular mandarin and plum varieties, is just a region of Japan. Be careful what you ask for if you're visiting: they don't call them "satsumas" there, but they do apparently use the term for a type of sweet potato! From a blog: "The area of Satsuma is not famous for tangerines and so it's very strange for us Japanese that Satsuma indicates tangerines in English."

What is a bud sport?

It is a naturally occurring mutation on a branch that differs sufficiently to be noticed and propagated as a separate variety. They occur in many plant, including roses and fruit trees and especially citrus. Bud sports may differ in size, color of the flesh or peel, how early they ripen, variegation of the foliage, etc.. For example, I sometimes get Dobashi Beni Satsuma trees from one grower, "reported to be a limb sport of Owari in the orchard of K. Dobashi in 1940 [in Japan] … Distinctive only because of its deep orange-red color."

What are some other mandarins?

Clementine is another great-selling variety. It ripens later and has somewhat tighter skin. There are several clones of Clementine. In some cases, particularly some earlier-ripening clones, seed is produced when the flower is pollinated. Seeds in a mandarin reduce the market value, so growers want to isolate them from bees to try to keep them seedless. This has led to a dispute between beekeepers and Clementine growers, as the citrus growers want bee-free zones of two miles around their groves!

Cuties® is a marketing device for selling smaller Clementine and Murcott mandarins.
Similar-sounding Pixie is a new variety of mandarin that ripens later and holds up well after harvest, so it extends the mandarin season. There are others: Four Winds Growers in Winters lists 13 different varieties of mandarins for our region.

Why is the fruit sweeter after a frost?

It is the conversion of malic and citric acids to sugars that makes the fruit palatable, and this tends to occur with cold temperatures. Conversion of acids and starches to sugar creates a natural anti-freeze in fruit, leaves (kale leaves are sweeter after frost), stems (maple syrup!), and roots. Preferably not hard freezing temperatures for citrus, as that causes breakdown of the flesh into undesirable off-flavored components and releases bitter compounds from the membrane.

A freeze can do considerable damage to the crop from damage to the trees, but also by making the fruit unusable even for juice. If the growers move fast, they can harvest and process the fruit quickly before off-flavors develop. When a regional freeze threatens, you may see workers harvesting citrus in the middle of the night!

Which ones can we grow?

All mandarins grow readily here, and varieties can be selected for early or later ripening. For example, Owari + Clementine + Encore + Pixie provides fruit from November nearly into summer. The small trees can be planted quite close together to maximize fruit production in a small yard.

Mandarins are among the cold-hardiest citrus. Four Winds Growers recommends frost-protection at 28 degrees, but my Owari trees and fruit have tolerated temperatures into the low 20s without damage. Gold Nugget and Yosemite are new patented varieties that are even more tolerant of cold.

Growing tips!

These small, slow-growing plants can be trained as shrubs or small trees, and can be kept in large containers for many years.
As with all citrus:

"where the cat sleeps in the sun, citrus grows well;"

Expect fruit beginning in 3 - 4 years, with yields increasing each year thereafter.

How many chilling hours do we get?

2010-12-14T10:28:00.000-08:00

We get lots of questions about "chilling hours" -- the number of hours between 32F and 45F that deciduous fruit trees need in order to break dormancy and flower properly. You will often see the number of hours that a particular variety needs printed right on the label; e.g., Elberta Peach 800 hours. Gardeners in the Bay Area and Southern California may not get sufficient chilling for many varieties, and need to inquire locally about which are recommended for their area.

I've attached an image showing the 15-year trend in chilling for Davis, Ca. Note that the first year shown (1995-96) was unusually low. Chilling hours in the Davis area typically range from 800 - 1000, allowing us to grow nearly any fruit variety available.

For the chilling hours in your area, check this website which shows weather stations all over California:
http://fruitsandnuts.ucdavis.edu/chillcalc/index1.htm

Frost Warning? Freeze Warning?

2010-11-24T17:46:00.000-08:00

Written for the Davis Enterprise, November 24, 2010

Click on any image for a larger version

"He comes, - he comes, - the Frost Spirit comes!

On the rushing Northern blast ... " John Greenleaf Whittier

What weather conditions lead to a frost warning?

What would prevent the frost?

"The Frost performs its secret ministry,

Unhelped by any wind." - Coleridge

What's the potential for harm in the garden?

A frost is not a freeze.

Which plants are we going to lose on a frosty night?

Pansy 'Delta Premium' -- no need for protection!

Which plants should we protect from frost?

Some succulents such as jade plant, some aloes, and kalanchoes.
Tender subtropicals such as hibiscus and mandevilla.
Semi-tender subtropicals such as bougainvillea, Guatemalan avocado, Mexican lime, young lemon and citron trees.

Which plants should we protect from a freeze?

There are two main ways to protect plants:

Trap heat.

Using frost blanket to protect fruit on a mature lemon tree.

Provide heat.

Fall Color in the Sacramento Valley!

2010-11-08T23:10:00.000-08:00

Why do leaves turn color in the fall?

This is right up there with 'how do they grow seedless watermelons?' among the most-asked questions directed at plant professionals.

The answer is simple! The days get shorter, the nights get colder, and Jack Frost magically paints the leaves in your yard!
Well, actually, the answer is more complicated, involving daylength (actually nightlength), temperature, nutrients, and genetics.

Trees that have adapted to cold winter climates go through several steps as winter approaches. The first part of the process is a reaction to longer nights. The plant forms a layer at the base of the leaves that blocks the movement of carbohydrates (sugars, starches) out of the leaves, and blocks the movement of minerals into the leaves. That 'abscission' layer eventually gets brittle and breaks, so the leaf falls.

October Glory maple

But before that happens, the plant produces less and less chlorophyll because it has less stuff to make it from. That is the pigment which makes leaves green. It is also the most fragile pigment, breaking down in sunlight very quickly. Usually the plant is replenishing it very quickly. But as it breaks down and becomes less abundant, the less common pigments of yellow and orange become visible. So these are the first fall colors that we see. Those colors were already there; we're just seeing them now because the green is gone. This first reaction mostly follows the calendar, although severely drought-stressed plants will begin to go dormant earlier than normal.

Some minerals are mobile within the plant, moving from one place to another as needed. The plant moves phosphorus out of the leaf and into the stem where it is stored during cold weather. The absence of phosphorus changes the chemical reaction in the leaves, and the remaining trapped carbohydrates are now made into certain other pigments, notably the ones that are red and purple. So these are the more spectacular colors that we see next. They weren't there before; the tree is making them now out of what's left in the leaf.

Chinese pistache leaves

Some trees make more of these pigments than others do, so it varies between species. There are also genetic differences of seedlings within a species. Variation in temperature from year to year, and the nutrient status of the specimen, also affects fall color. Within those species that have the pigments to begin with, sunny clear days and cool nights encourage the production of more red and purple pigments. A tree with adequate nutrition will have more basic material to work with to create pigment. Trees that are overwatered have damaged root hairs, so they've been unable to take up nutrients readily during the summer.
Click here for more of this article, and pictures

20 Easy Fragrant Plants

2010-10-28T19:28:00.000-07:00

Plant people get excited about strange things. A breeder developing a yellow Salvia. A single-flowered variant of Lady Banks rose. A white daylily. These are the things that get plant collectors all a-twitter. Or a plant re-surfacing after many years.

Osmanthus fragrans 'Aurantiacus'

When I first moved to Davis to attend UC Davis I lived in the Primero dormitories located along Russell Boulevard. As I walked by the Student Health Center on my way to class, I noticed a powerfully fragrant shrub blooming in spring and fall. The flowers were nondescript and the foliage was a drab green-olive color, so one hardly noticed the plant itself. The fragrance resembled peaches and apricots, with sharp sweet notes, like a fine liqueur. Osmanthus fragrans: commonly called sweet olive. There was also a plant located near the Memorial Union building before it was remodeled. The former had white flowers; the latter had orange ones and bloomed more heavily in the fall.

Alas, Primero dorms are gone, though not lamented: they had no A/C and had antiquated heaters; gone also are both of those shrubs. In my mind's eye I can still see each one, more than 35 years later. As a nascent student of horticulture, anything with an aroma like that would distract me as I crossed campus. My bike got totaled, and then stolen, within a month of my arrival here, so I gave up on bicycles. I was a pedestrian on campus for all of my student years, which enabled me to see the plants close up that 99% of the students whizzed past.

Recently the orange variety came through my store for the first time I can remember. Osmanthus fragrans 'Aurantiacus'is the official name. "Fragrans" is self-explanatory, and "Aurantiacus" is Latin for orange. This Osmanthus species is native to Asia; flowers are used in tea, jam, and liquor and various Asian dishes.

The flowers of 'Aurantiacus' are pumpkin-orange, appear mostly in autumn, and each flower is only about one-quarter inch. Not spectacular, but it would be difficult to overstate the powerful fragrance of these tiny flowers. Everyone who walked by the evergreen shrub raved about the scent. As with many fragrant flowers, the volatile oils evaporate and drift several feet from the plant.

Common O. fragrans is readily available, but 'Aurantiacus' is hard to propagate and very rare in the trade. I don't know how this grower produced it, and as soon as they released their small crop it was gone. Both grow with an open habit, at a moderate pace of 2 to 3 feet a year, ultimately becoming ten to fifteen feet tall with about half that spread. They tolerate sun, but look best with protection from the hottest sun of the afternoon, and will also grow and bloom in bright shade.

Osmanthus is just one of many easy landscape shrubs providing rich fragrance without special attention. In fact, along with certain perennials and annuals, it is possible to plant a garden of easy plants for fragrance year-around. Here are some choices, sorted by season of bloom.

Fall-blooming

1. Brugmansia
Common name: Angel's trumpet.
A big shrub with bold leaves, growing to 10 feet +. Hardy subtropical. Tops are damaged in winter, sometimes killed to the ground, but it always resprouts. Appearance is best if it is sheltered from hot sun and wind, and frost protection prolongs the late fall bloom. Blossoms are intoxicatingly fragrant, but only at night. All parts are poisonous.

2. Osmanthus fragrans 'Aurantiacus'
Common name: Orange tea olive.
Hardy evergreen shrub best in partial sun or shade. Full morning sun is ok. Drought tolerant.

Winter-blooming

3. Sarcococca ruscifolia
Common name: Victorian box.
Slow growing evergreen shrub to 3 to 4' tall and wide, easily clipped as a hedge. Little white flowers in January smell like gardenias! Very shade tolerant, burns in any direct sun. Drought tolerant.

4. Wisteria species: W. sinensis, floribunda, and venusta.
Common name: Wisteria.
Very vigorous deciduous vine with purple or white flowers in late winter.
Blooms best in full sun and under dry conditions.

Spring-blooming

5. Citrus
Evergreens grown as shrubs or trees. April blossoms are intensely fragrant. Meyer lemon flowers and fruits year around. Kumquats bloom in summer. Hardiness varies: mandarins are hardiest; limes are tender.

6. Jasminum polyanthum
Common name: Winter jasmine.
Very vigorous evergreen vine that can take over part of your yard. Pink buds open to pungent white blossoms in Feb. - April, depending on weather.

7. Lathyrus odorata
Common name: Sweet pea.
Annual vine that we plant from seed in fall for winter and spring bloom.

8. Philadelphus
Common name: Mock orange.
Deciduous shrub grows pretty fast to 8 feet tall, 5 to 6 feet wide. There are dwarf varieties. Open, somewhat rangy habit. Lemon-scented blossoms in May. This is what east-coasters call Mock orange.

9. Pittosporum tobira
Common name: Mock orange.
Common evergreen grows 2 to 3 feet a year to 10 feet or more; readily pruned to any height. Lemon-scented blossoms in April and early May. This is what Californians call Mock orange.

10. Rosa banksia
Common name: Lady banks rose.
Gigantic evergreen, thornless climbing rose. Very tough. Blooms for a couple of weeks in early spring before the other roses begin. The yellow and single white forms smell like cotton candy. Best in full sun. Very drought tolerant.

11. Syringa vulgaris
Common name: Lilac
The familiar hardy deciduous shrub from colder climates grows fine here and blooms freely in full sun or light shade. Very drought tolerant.

12. Osmanthus fragrans
Common name: Sweet olive.
The white form blooms most in the spring.

Spring and Summer blooming

13. Dianthus
Common name: Pinks, carnations.
Hardy perennials that can last for years. The grey-leaved forms are tougher garden plants than the green-leaved ones (which are usually sold as annuals, though they will live two to three years). Many Dianthus have strongly spice-scented blooms.

14. Phlomis fruticosa
Common name: Jerusalem sage.
Tough shrub with fuzzy grey-green leaves, grows to 4 to 5 feet tall and 6 feet or more across. Blooms in waves in spring and summer. The strange-shaped whorls of bright yellow flowers smell just like carnations! Tolerate extreme sun, heat, and drought.

Spring, summer, and fall blooming

15. Rosa hybrids
Common name: Rose
Obviously roses belong on any list of fragrant shrubs. Look for varieties noted for their scent, as many hybrids have light or no fragrance. Roses like full sun and lot of water.

Summer blooming

16. Fortunella margarita
Common name: Kumquat.
This evergreen citrus, which grows as a large shrub or small tree, is the hardiest of all. The summer flowers are smaller than other types, but very fragrant. The fruit is a nice ornamental and edible bonus, hanging on the tree year around.

17. Jasminum officinale
Common name: Poet's jasmine.
Hardy evergreen vine that blooms in the summer. Much less invasive than the spring-blooming jasmine, the bloom is less abundant but lasts longer.

18. Trachelospermum jasminoides
Common name: Star jasmine.
This evergreen vine hardly needs introduction. The fragrance is too powerful for some people Very drought tolerant and grows in anything from full sun to full shade (though bloom is limited in shade). Very drought tolerant.

Fragrant foliage

19. Aloysia triphylla
Common name: Lemon verbena.
Open, airy shrub with yellow-green foliage that is packed with citronella aromatics. It gets 6 feet or more tall and broad. Either prune it to enhance the open form, or cut it back hard every couple of springs. A hardy subtropical, it often loses leaves and might even die back during freezing weather, but always resprouts.

Blooms year-around

20. Lobularia maritima
Common name: Sweet alyssum.
Easy-to-grow annual flower that reseeds all over your yard. The honey-scented blooms can be present all year around once you have an established population. Pink and purple forms will reseed lighter, eventually white. Best in full sun or very light shade. Very drought tolerant.

Also-rans ("why didn't you mention....?"):

Ceanothus species and hybrids: Mountain lilac.
Fast-growing shrubs and ground covers are very drought tolerant but also easy to kill by watering too often. Blue, purple, or white blossoms in spring smell like honey.

Cestrum nocturnum: Night-blooming Jessamine.
Dies back to the ground most years, but usually resprouts. Powerful fragrance at night only. Poisonous.

Daphne odora: Winter Daphne.
Spicy lemon-scented blooms in winter. So, so, so easy to kill. Poisonous.

Elaeagnus species.
Cousins of Russian olive, several species of Elaeagnus have sweet-scented clusters of flowers. Very tough, informal shrubs for rural areas or large hedges; in small yards they'll need a lot of pruning. E. ebbingei 'Gilt Edge' has strongly variegated leaves and a manageable upright habit. The fruit are edible (I'm told) and popular with songbirds. Very drought tolerant.

Gardenia jasminoides.
Not happy about our alkaline water, so it gets anemic without special fertilizer. Blooms best where it gets morning sun, afternoon shade.

Jasminum sambac: Arabian jasmine.
The wonderful Pikake of Hawai'i. Tender even to a light frost, it must be indoors in winter here.

Lonicera species: honeysuckles.
I hesitate to recommend the most fragrant (and most common) species, L. japonica, because it is very invasive.

Here is a substitute, although it is rare:
Lonicera hildebrandtiana
Common name: Giant Burmese honeysuckle.
Fast-growing evergreen subtropical vine with large, shiny leaves, it is just hardy here, showing damage after severe frost but usually recovering. Giant blooms have exceptional fragrance. Difficult to propagate, it is usually grafted onto L. japonica, so watch carefully for any root suckers and remove them immediately.

Passiflora species and hybrids
Passion flowers and passionfruit. Many hybrids have spicy-scented flowers. Variable hardiness, and some are rampant. Choose accordingly.

Scented geraniums (Pelargonium species).
Easy to grow, somewhat frost tender. Expect to replace them every year or so.

A gallery of fragrant plants

click to enlarge

Brugmansia
Angel's Trumpet ('Charles Grimaldi' shown here)

Osmanthus fragrans 'Aurantiacus'
Orange tea olive

Sarcococca ruscifolia Sweet Victorian box

Wisteria species 'Cooke's Purple' shown here

Philadelphus Mock orange

Pittosporum tobira Mock orange

Syringa vulgaris Common lilac

Dianthus barbatus Sweet william

Phlomis fruticosa Jerusalem sage

Rosa moschata 'Nastarana'

Jasminum officinale Poet's jasmine

Lobularia maritima Sweet alyssum -- 'Easter Bonnet' shown here

Ceanothus Wild lilac

Cestrum nocturnum NIght-blooming jessamine

Gardenia jasminoides 'August Beauty' shown here

Passiflora Passion flower -- 'Purple Tiger' shown here

Sir, can you get me a pawpaw?

2010-10-01T15:35:00.000-07:00

Do you really want a pawpaw?
Asimina species

Why aren't these common in the nursery trade?
1. You need two trees of different varieties to cross-pollenize.
2. Crushed leaves smell like diesel fuel. Mmmm.
3. Pollinated by carrion flies and beetles, the flowers smell like rotting meat. This alluring idea comes from a web site: “I have hung chicken bones to attract carrion flies to the flowers, and others have used this practice to improve pollination.” Or this from Wikipedia: “Growers of pawpaws sometimes place rotting fruit or roadkill meat near the trees at bloom time to increase the number of pollinators.”
Charming.
4. The fruit flavor is low-acid, often described as like bananas or custard. It ripens quickly, with a soft texture. Each fruit has numerous large seeds, so it is mainly eaten as pulp. If they are pollinated and pollenized correctly, yields are high. Imagine large amounts of custard-like fruit with very short shelf life all ripening at once.
5. The trees are tap-rooted and the roots are fragile, so they aren’t common in the nursery trade; trees with those characteristics have notoriously high failure rates.
So no, I probably can't get you a pawpaw. Perhaps the great folks at ForestFarm in Oregon can help you out:
http://www.forestfarm.com/product.php?id=635

Vintage Gardens: A Garden For Beneficial Insects in the Wine Country

2010-09-24T14:06:00.000-07:00

Wine & Roses? How about Wine and Yarrow?

On a recent hot summer day, I escorted my daughter and a friend through Napa Valley so they could go wine tasting. Many of the wineries feature colorful garden beds to lure passing motorists, and it always interests me to see what the latest trends are in this fashionable district where cost, it seems, is no object in beautifying the grounds.
Zinnias are in. Beds that used to be planted in marigolds and petunias are now being filled with these colorful, gaudy flowers. Zinnias and asters were popular many years ago, before marigolds supplanted them in the 1960's and 70's. Petunias added a range of colors not found in other flowers, including vivid purples and true blue. But marigolds get spider mites and petunias get caterpillars. Zinnias don't get either of those.

Bed of zinnias in August at Turnbull Wine Cellars
Ok, you might not get this excited about a bed of zinnias. But the range of colors and abundance of bloom makes them ideal for eye-catching annual borders. Resistance to spider mites and caterpillars make zinnias a suitable replacement for marigolds and petunias in the summer border. While you are at Turnbull, check out the amazing collection of vintage photographs!

Zinnia flower at Mumm Napa, champagne vintners, Rutherford. (Click on any image for a larger version).

The recent popularity of succulents and ornamental grasses has led to a very different look in formerly formal garden beds. The grasses can look a little rangy without some grooming. Succulents such as Echeveria (Hen-and-chicks) and Sedum (Stonecrop) provide colorful foliage with compact, tidy growth habits. With the drought tolerance of both groups of plants, this is a positive trend.
One of the more interesting planting ideas I saw was at the upscale delicatessen in St. Helena, Dean & Deluca. Around the blazing hot walls they had placed two-foot long, one-foot wide aluminum irrigation troughs such as you would find at feed stores. These were planted with clipped boxwood hedges and assorted succulents. The mix of formal and southwestern plants in a rural "planter" was eye-catching, and the plants were thriving in the brilliant sun with apparently little care. Irrigation troughs provide considerable soil volume to retain moisture. You can find these at Higby's Country Feed store outside of Dixon on Currey Road.
Napa Valley has changed over the three-plus decades that I've been visiting. Disappearing are the Redleaf plums and roses that used to be planted along the edges of vineyards. Now you see olive trees in every niche along the roadsides. Aesthetically pleasing as this is (northern Italians must feel right at home), I can only imagine what it is like during allergy season: both grapes and olives are wind-pollinated.
A lot of the wineries seem more focused on their tasting rooms than on their wine. One that we stopped at, briefly as it turned out, seemed more concerned with the faux-Italian marble exterior and flooring, the fancy fountains, and the ornate formal driveway. My young visitors didn't even bother with the wine tasting there ("what is this, Disney does wine country?!?"). I was perplexed by the butchery of the old olives in the parking lot. Venerable trees had been stubbed off. Bah.

Sunflowers up the hill at Benziger
But another big change that is occurring gradually in the Napa Valley is the transition to safer, environmentally-sensitive ways of growing grapes. For many years grapes have been a heavily sprayed crop, treated with pesticides and grown in clean rows of bare dirt. The costs, tangible and otherwise, of these old techniques are becoming apparent to a new generation of viticulturists and vintners.
So we were delighted when we got off the main road a bit and found the Benziger Family Winery. The grapes are grown organically. The soils and vines are managed sustainably. The vineyard has certifications for sustainable practices and organic production. The vineyards are Demeter-certified biodynamic. "Instead of bagged fertilizer, weed killer and pesticides we rely on composting, natural predator-prey relationships, cover crops, and the animals that live on our estate, to keep our vineyard healthy and balanced."
There are lovely gardens around the tasting room, of course. Sheep and goats graze through the vines (carefully). Horses draw plows. Owl and bat boxes abound, up on high poles. A large, rather scummy pond attracts birds and dragonflies. And most important from a gardener's standpoint, they have two display gardens devoted to attracting and retaining beneficial insects, including pollinators and pest-eaters.

Garden at Benziger Family Winery
This tranquil sitting area was buzzing with activity! I counted five different types of bees on nearby flowers. Syrphid flies and tiny beneficial wasps abounded. Dragonflies circled the water and perched on the horsetails. The key is the mix of water, shade, and sun, with a diversity of plants chosen to provide habitat, resting sites, and food for beneficial insects and birds.

So as the young ladies enjoyed the cool comfort of the tasting room, I wandered the grounds. Since the temperature at that moment was 104F, I had the place pretty much to myself. When Noel Coward said "Mad dogs and Englishmen go out in the midday sun," he might have added gardeners who spot distant flowers.

The purpose of the gardens was to provide for birds, bees, and beneficial insects. When you do that, you want to provide:
o cover for birds and lizards
o moving water to draw dragonflies, and upright-growing plants for them to perch on.
o still water with basking rocks for smaller insects to drink
o tubular blossoms for hummingbirds and butterflies
o tiny flowers in clusters for small beneficial insects to feed on pollen and nectar
o cool shade for toads and people
o tall trees or poles for birds, as well as the aforementioned bat and owl boxes.

Solidago (goldenrod) with Aster

The closest display garden featured a small pond with a recirculating fountain whose water splashed down a course of shallow bowls. Nearby horsetail (Equisetum) provided natural perching points for dragonflies, which are voracious entomophagous beneficials: they eat whiteflies. A large bed of ornamental sunflowers provided dramatic color and was very active with bees and syrphid flies (aka hoverflies; their larvae eat aphids). The combination that gained the most attention was toward the back of the bed: dark purple asters next to bright goldenrod (Solidago). Each goldenrod plant was swarming with hundreds of bees of varying species, hoverflies, and tiny parasitoid wasps that were feeding on the pollen or nectar.

Other plants in the garden include lavender, mallow, Russian sage, and tansy. Except for the annual sunflowers, all of the plants I've mentioned are perennials, easy to grow, and drought tolerant. None require special soil or attention. This is a garden where you mix plants with differing foliage textures and bloom seasons, groom them occasionally, and sometimes pop in a new one when something gets overgrown or untidy. All could get by with as little as a deep soaking once a month.
There are lots of other plants that attract beneficial insects. Many California natives, herbs, and flowering annuals make the list.
Here are just a few that you can plant now to make your garden friendlier.
Perennials and annuals:
Borage (Borago officinalis),
Daisies of all types,
Sweet alyssum (Lobularia maritima),
True alyssum (Alyssum saxatile),
Yarrow (Achillea species).
Shrubs: California lilac (Ceanothus), Buckwheat (Eriogonum).
Herbs: fennel, cilantro, mint, mustard, rosemary.
Cover crops (plant from seed to build soil in your vegetable garden): soybeans (plant in summer), clover and vetch (plant in winter).

For more information about Benziger Family Winery grape-growing and wines, visit their web site at http://www.benziger.com/.

Some plants for beneficials

click to enlarge

Achillea Red Beauty -- Yarrow

Borago officinalis -- Borage

Solidago -- Goldenrod, closeup of flowers

Written for the Davis Enterprise, September 23, 2010

© 2010 Don Shor, Redwood Barn Nursery, Inc., 1607 Fifth Street, Davis, Ca 95616

www.redwoodbarn.com

Feel free to copy and distribute this article with attribution to this author.

Click here for Don's other Davis Enterprise articles

Cool Season Vegetables!

2010-09-07T22:03:00.000-07:00

Food we plant in Fall

We have two complete seasons for vegetable gardening in the Sacramento Valley! September thru November are ideal for planting many leafy greens and root crops for winter and spring harvest.

Bean

Beets

Broccoli

Brussels Sprouts

Grown for lateral buds on flower stems. Tricky; needs a long season. After July may be too late! Aphids are a hassle to manage. Many people don't like the flavor due to a genetic characteristic which makes them sensitive to bitter compounds in the sprouts; other people don't even taste that.

Cabbage

Carrots

Cauliflower

Celeriac

Celery

Celtuce

Chard, Swiss

Chicory, Belgian endive

Cilantro, coriander, Chinese parsley

Collards

Corn Salad

Cresses

Endive, Curly; Escarole

Fennel, Florence

Garlic

Kale

Kohlrabi

Leeks

Lettuce

Mustard greens

Onions

Onions, bunching

Oyster plant, Salsify

Pak-choi

Parsley Root

Parsnips

Peas: Edible-pod, Sugar, Snow

Peas: Shelling

Potatoes

Radicchio

Radishes

Rutabagas

rotabagge

Spinach

Turnips

Click here for a planting chart!


  
A harvest of winter vegetables! All can be planted in fall for cool season harvest Clockwise from bottom left: beets, baby pak choi, kohlrabi, parsnips, radishes, carrots, radicchio. Center: celeriac.
Click here for more information about cool season vegetables.
See also Winter vegetables



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   © 2008 Don Shor, Redwood Barn Nursery, Inc., 1607 Fifth Street, Davis, Ca  95616
  www.redwoodbarn.com
Feel free to copy and distribute this article with attribution to this author.           Click here for Don's other Davis Enterprise articles

Some like it hot(ter)

2010-08-26T15:36:00.000-07:00

Item: Sacramento's tomato season shaping up as short, sweet

From home gardener to commercial growers, tomato season has been especially challenging this year. "It's August but feels like May," said Suzanne Peabody Ashworth, who grows more than 60 varieties at her Del Rio Botanical farm in West Sacramento.
"This has got to be the latest tomato season I've ever seen. I can't remember a summer quite so cool."

Item: Temperatures continue well below average in Southern California

It hasn't been the coolest summer on record, but it's been close, forecasters say. The average temperature in July was 79 degrees, five degrees below normal, and the first eight days of this month also have been five to six degrees below normal, weather experts said.
"The fruits and vegetables, the tomatoes and a lot of the citrus and things like raspberries are not ripening up because it's not getting hot long enough," [said an expert from the LA county arboretum], adding that some fruit could taste less sweet because "less sun means less sugar content."

Why aren't my vegetables producing?!

Tomato inflorescence
What's going on? This bloom cluster on a Roma tomato illustrates the problem. Tomato flowers open gradually along the cluster toward the end. The first, oldest flower set fruit. Temperatures when the next two flowers opened were very cool at night, with one night dropping to 48 degrees! Those blossoms have not set, and will fall off. The bloom currently open will probably set. So this cluster is setting fruit on about 50% of the flowers.

Some other problems from our odd summer weather.

Fireblight!

Crataegus

Raphiolepis

Fireblight on an apple tree
Fireblight is caused by a bacterium called Erwinia amylovora. It attacks specific members of the pome group of the rose family, particularly apples and pears, infecting through the blossoms or the young tender growth. The disease kills the flowering wood and spreads rapidly down the stem. The common name refers to the fact that it blackens the wood as it kills the shoots and branches, so the plant looks as though it has been burned. Prune it out!

Powdery mildew, particularly on sycamores and plane trees.

Powdery mildew on a plane tree

Disease resistant Platanusvarieties

The best way to deal with disease problems is to prevent them in the first place. Sycamore leaves attacked by powdery mildew (photo, left) are curled and distorted and covered with white powdery material; leaves attacked by anthracnose blight fall off after spring rains. Two varieties ofPlatanus (above) have good disease resistance. The Roberts variety of California sycamore (P. racemosa, above left) resists anthracnose. Columbia variety of plane tree (P. x acerifolia, above right) resists both anthracnose and powdery mildew.

crown rot

Phytophthora

nutritional deficiencies

Written for the Davis Enterprise, August 26, 2010

Bamboo FAQ's

2010-07-22T20:24:00.000-07:00

Written for the Davis Enterprise, July 22, 2010

from a presentation to the Yolo County Master Gardeners July 14, 2010

FAQ's (frequently asked questions) about bamboo

I recently spoke to the Yolo County Master Gardeners about bamboo, for the second time in a decade. When I last met with this group in 2002, I used a slide projector and sorted the slides by hand. Some things have changed; now it's a PowerPoint projector, and I sorted the images on Graphic Converter.

But the common questions haven't changed much since my father was president of the American Bamboo Society in the 1990's, when he was the primary phone contact for bamboo-related questions from the public and media. All in the family: my mother and I now edit BAMBOO, The Magazine of the American Bamboo Society, so we frequently get the basic bamboo questions from the public. Here are the top questions, then and now.

Is all bamboo invasive?

No! Bamboos have several rhizome types, but they can be grouped into "clumpers" and "runners." Running bamboo can be very invasive, spreading several feet in a single year. Clumping bamboo spreads slowly, taking up about as much space in the yard as a large shrub. They're easy to tell apart: the stems of running bamboos are ridged or grooved. The stems of clumpers are perfectly round.

Phyllostachys species showing ridge on culm. It's easy to tell running from clumping bamboo: runners always have a ridge or groove on the culm, whereas culms of clumpers are perfectly round. Check the label: in this area, most common runners are in the genus Phyllostachys. Most common clumpers are in the genus Bambusa. But bamboo can be mislabeled, so it's wise to double-check!

Can running bamboo be controlled?

Yes, but any method of confinement must be monitored. The rhizomes grow in a straight-ish line, and if they hit a barrier they will grow along it, under it, or over it. Bamboo barriers are made of 40 - 60 ml plastic, installed in a trench and left sticking up a couple of inches above ground. Walk the line every year and snap off any rhizomes that have grown over the barrier. Don't allow leaf debris to build up over the barrier, or rhizomes will happily push unnoticed through the leaf mold and root as they do so.

Some other options:

o Bamboo can be planted in lawn areas and maintained by keeping the grass clear for several feet past the grove, usually with herbicides. Rhizomes and shoots that show up are then dug out. Done annually, this isn't too arduous.

o Concrete contains bamboo, although rhizomes have been known to grow along the expansion joints that are left in paths and driveways.

o A trench filled with coarse gravel or cobble provides a visible line to follow and watch for rhizomes.

o Rhizomes will not grow into dry soil, so unirrigated areas provide a natural barrier. Rhizomes also will not grow far into open water. A moat or pond can contain them.

o Running bamboo is excellent in a container. The rhizomes simply circle around and around, eventually getting quite root-bound, so the plant will need frequent watering after the first year or so. But bamboo can survive and look attractive for many years, even when totally root-bound.

Of course, it is simpler to just plant clumping bamboo in the first place.

How do I get rid of running bamboo?

From an article my father wrote for the American Bamboo Society years ago:

"Cut it off.

Cut it down.

Water the area.

Cut it down again.

And again."

Plant the right bamboo next time!

Cut it off: cut the rhizomes to separate the plant from the main source (your neighbor's bamboo). Cut it down: cut all the culms to the ground. Rhizomes that don't have leaves to support them will slowly starve. But they resprout quickly, so water the area to get them to do so. Then cut them down or dig them out again, as many times as necessary.

Will herbicides help during this process? Possibly. Many people use glyphosate to try to kill the root system. It works best, if at all, when it is sprayed on as much leaf area as possible. Bamboo has a lot of stem, and the leaves are way up high. So it is best sprayed when it has been cut and resprouted to make the leaves more accessible. Applying herbicide to the cut stems doesn't really work.

How do I plant a bamboo hedge?

Clumping bamboos make the best hedges, as they have the leaf density you are after. Varieties of Bambusa multiplex are most effective, to the point they are often called "hedge bamboos."

The expensive way is to buy a bunch of clumping bamboo plants and install them 4 - 5 feet apart. They will double in height each year, and expand slowly outward, creating a wall of bamboo in a couple of years. To save cost, you can plant 8 - 10 feet apart, plant a vine on the fence for quick screening, and plan on dividing the bamboo clumps every 2 to 3 years to fill in the gaps.

A well-established, unpruned hedge of one of the best clumping bamboo varieties for our are: Bambusa multiplex 'Alphonse Karr'. This one features golden-striped culms and dense, yellow-green foliage.

Bamboo is about double the cost of other shrubs, because it is slow to propagate and is a niche nursery product grown by specialty nurseries. It takes almost an extra year for the grower to get a marketable plant, compared to common landscape shrubs.

Is it ok to prune bamboo?

Certainly! You can hardly hurt it. Just be aware of the growth cycle so you avoid having it look like a bad haircut. A bamboo shoot divides until it is fully formed, ready to expand rapidly in the spring or summer (depending on type). Then it expands telescopically, growing from ground level to full height in as little as 30 - 60 days. This is pretty remarkable, considering that some of our species grow to 30 - 50 feet tall!

Prune bamboo? Sure! This amazing bamboo labyrinth is at Bambouseraie in Prafrance, southern France

Once the culm is fully grown, it will not get any taller. In the case of clumpers, it will also not leaf out until the following spring. Wait until it is fully grown, then you can cut it to the height you want and it will stay that way. One annual pruning can shape bamboo.

How fast does bamboo grow?

Japanese researchers have measured daily growth from shoots into culms of two species at 46 to 48 inches in a 24 hour period! I have observed Bambusa beecheyana on my property grow from ground-level shoots in early October to 35-foot tall culms by late November.

Can I grow bamboo as a house plant?

Not really. Bamboo needs bright light, sheds leaves and culm sheaths, and is very, very, very prone to spider mites indoors. You will see it in professionally managed indoor environments such as shopping malls: indoor plant experts wash the foliage regularly to avoid mites, and apply systemic insecticides.

What about "lucky bamboo"?

It is not a bamboo. It is Dracaena sanderana. and is very easy to grow indoors. Although it can be kept pretty dry when grown in normal potting soil, this plant's amazing endurance when it is grown simply as rooted cuttings in water and pebbles has made it very popular. But we really wish it wasn't called "bamboo."

Dracaena sanderana, the "Lucky Bamboo" that isn't a bamboo at all!

Does bamboo die when it flowers?

Not necessarily. Bamboo sometimes just flowers due to stress and doesn't die. But it is true that individual clones of some bamboo species flower all at once, all over the world, on multi-decadal cycles, and that many species will then set seed and die. The cycles range from 30 to 60 years. My mother tracks the worldwide flowering records of bamboo, and it is interesting to watch the reports come in when, as happened recently, all the Fargesia nitida began to flower and die.

This "gregarious flowering" of bamboo species can lead to famine in some areas, as the massive seed production causes rodent population to soar, which then leads to depradation on other grain plants and stores. In Mizoram, northeastern India, cycles of famine linked to bamboo flowering have been documented back into the 19th century.

In China, it isn't so good for the giant pandas, as bamboo is ALL they eat. Often an entire mountain is covered with essentially one clone of a particular running bamboo, which flowers and dies. Sometimes they airlift bamboo to the pandas, sometimes they airlift the pandas to nearby bamboo.

Flowering is a plus for horticulturists because they have seeds to sow and interesting new varieties emerge from the seedling trays. These are named and propagated by clonal production, starting a whole new generation of cultivated varieties (cultivars), which should be good for another 30 to 60 years.

What is eating my bamboo?

You name it! Not much eats bamboo leaves and stems (except pandas), but LOTS of things eat bamboo shoots! We have received reports of squirrels, gophers, tree rats, packrats, opossums, voles, various birds, snails and slugs, feral pigs, armadillos, and more. My parents have large clumps of bamboo along an alley behind their house in San Diego, and had a problem with the shoots disappearing. The culprits were two-legged hominids.

Can I eat my bamboo shoots?

Most can be eaten if they are not bitter. Not all bamboo makes palatable shoots. If they are bitter, they may contain cyanogens, which can be removed simply by cooking the shoots.

Is bamboo drought tolerant?

Tolerant is the operative word. Bamboo loves water; most species are adapted to monsoon-like rainfall cycles as their shoots expand into culms. It is nearly impossible to over-water bamboo. But it can survive drought; plants will simply stop growing, and then start dropping leaves. Give it water, and it will re-foliate pretty quickly. This is why they are very amenable to being grown in containers: bamboo can survive drought and recover quickly. But it isn't what bamboo prefers.

A rhizome is a stem which grows at ground level, just above or below the soil. It produces roots at each node, and shoots at intervals. If the nodes are close together, and the rhizome ends in a shoot, the plant forms a tight clump. If the nodes are widely spaced and the shoots branch off a continuous stem, the plant forms an open grove.

Photo courtesy of Texas Bamboo Society; illustration by Bob Clune

Glossary:

o rhizome: horizontal stem which grows at ground level, rooting at the nodes and sending up shoots at intervals.

o shoot: the fully divided, ready-to-grow culm, before it expands. We eat bamboo shoots.

o culm: the fully grown, expanded shoot. Pandas eat bamboo culms (and leaves).

Check Daily, Water As Needed

2010-07-20T09:37:00.000-07:00

Summer Planting in the Sacramento Valley

Simple answers don't begin with 'that depends.'

When people ask me how they should water their newly transplanted trees and shrubs in the summer, my answer is often not simple. It begins with 'what are you watering with?' Then we may need to discuss what type of soil they have, what kinds of plants, and so on. But gardening is full of rules of thumb, guidelines that are easy to remember. After all, gardening is a mix of science, skill, and art. So let's come up with a simple answer to the question: how should I water new plants during the summer?

Let's get one myth out of the way first: 'It's too hot to plant here during the summer.' Nonsense!

Landscape contractors don't stop working in the summer. Ideal temperatures for plants to establish and grow are 55 – 90 degrees (F), which is the majority of our summer temperature range. A plant that can grow in our climate can sustain short periods of very hot weather, even shortly after transplant.

There are advantages and disadvantages to every season here.
Some advantages of summer planting?

Plants root quickly into warm soil, establishing faster than in winter or spring.

You have greater control over soil moisture, so you can dig a proper planting hole. Water thoroughly a couple of days beforehand, and the soil will be perfectly workable.

Many plants prefer warm weather: subtropicals and plants from Mediterranean climates, for example. Citrus trees planted in late winter often sulk, whereas those planted in summer begin immediate growth.

Availability and quality from wholesale growers are often better in summer. Propagation and production cycles of many plants have them retail-ready in summer: shade trees, subtropicals, and Crape myrtles are good examples.

The key to success, regardless of season, is proper planting and aftercare.

Most important is how you water. Our margin of error about watering is narrower in the summer. Plants should not be stressed to the point of wilt, while watering too often leads to crown- and root-attacking fungus. Therein lies the reputation that summer planting is difficult.

Aftercare includes the period of transplant stress and early root establishment.

When you take the plant out of the pot, you will find roots circling or bound up. Sometimes you have a solid cylinder of packed roots. Pull, tease, or even cut those roots to get them un-bound. Obviously that stresses the plant a bit. Exposing the fine root hairs to the air kills them, and those are the water-uptake part of the root. So the plant droops, even with adequate soil moisture. But that period of shock only lasts a few days: the fine root hairs re-grow immediately if the soil is loose, warm, and moist.

After the first couple of days, the roots quickly begin to grow out into the surrounding soil – especially if you have loosened it at the time of planting. This is why we recommend digging a hole at least twice as wide as the container, turning and crumbling and mixing the soil thoroughly. Full root penetration into the surrounding soil occurs within about six weeks, so that is how long it needs special watering attention.

So here is the first rule of thumb: check the plants daily, water as needed.

Simple enough. But what does 'as needed' mean?

You could wait until the plant starts to wilt slightly, poke your finger into the soil an inch or so, wait until it feels nearly dry to the touch.

Or you can calculate it.

Ok, so I actually have a degree in plant science. I should be able to calculate how much water a plant needs. The evapotranspiraton rate (ET rate) is a measure of how much water a plant uses, measured in inches (gallons per square foot). All you need to know is the plant's canopy (leaf area), look online at the weather data for Davis at ipm.ucdavis.edu, and you can calculate how much water a plant used. Let's see: 1' of water = 0.62 gallons per square foot. The ET rate on June 21 was .27' at the Davis weather station, so a 2' diameter plant used about ½ gallon of water (you still with me?) that day.

Now, I haven't accounted for the variation in ET rates by microclimate, because I have no way to measure ET on my own property. And plant species vary in their actual usage: the ET rate measurements are based on turf. So I'd need the coefficients for my particular species to multiply (stop yawning!) the ET figures, but that would, if anything, make the actual use rate a bit lower. I'd have to do separate calculations for each plant based on size and type.

I'm guessing most people won't find this approach very practical.

All right, let's try a more hands-on technique. At the nursery we water nearly every plant nearly every day during the summer. How much water does it take to get the nursery soil thoroughly wet? I tell my staff to count to five slowly for a #5 can, and to ten for a #15 can. The new plant in the ground is still mostly in the nursery soil for the first couple of weeks.

How much water does your hose put out? At full throttle about 7.5 gallons per minute. So here's how much we're watering each day:

4' pot: one quart

#1 can: 0.5 gallon

#5 can: 0.75 gallon

#15 can: 1 gallon

But there are a couple of issues with this approach once the plants are in the ground.

1. Daily watering in heavy soil encourages fungus that may kill the plant, especially in hot weather. It's better to allow the soil surface to dry slightly between waterings.

So here's our second rule of thumb: Water every other day, the following amounts:

* 4' pot: 0.5 gallon

* #1 can: 1 gallon

* #5 can: 1.5 gallons

* #15 can: 2 gallons.

You can do this with a hose or with a drip system. Most drip emitters put out 1 – 2 gallons per hour, so you'll need to run the drip line for 1 – 2 hours every other day.

My friend and associate, Deborah Flower, is a horticulture instructor at American River College. When she was a graduate student at UC Davis, she field-tested (literally) this approach with #1 and #5 size shrubs planted in a field near Old Davis Rd. She made a simple berm of soil around the nursery soil and watered the measured amounts by hand. She notes, 'when I used this system I did not lose a single plant!'

2. The soil around the nursery soil also needs to get wet, or the roots won't grow outward. So use a sprinkler or your existing system to water the surrounding soil thoroughly once a week. Set out some tuna cans to make sure you're applying 1.5 – 2 inches of water a week. (This, by the way, is how you should be watering established plants in your yard.)

In her experiment, Debbie accomplished this extra watering by thoroughly soaking the soil in a larger area around each plant.

Why not just use your sprinkler system for the new plants? Because the other plants in your yard don't need water that often. It is better to water the new plants individually. A simple drip watering system, or a soaker hose, is best for the new plants if you can't hand-water. Be sure that the drip emitter is positioned just over the nursery soil.

3. Debbie continues, 'they must be cautioned to not continue this frequency of watering once the plant is established!' So here's our third rule of thumb: keep it up for six weeks: that is, continue the individual every-other-day watering, by hand or with a drip line, for six weeks. A simple battery-operated timer can automate the process if you want to go on vacation. It's ok to give new plants an extra drink on a windy day.

A healthy plant, properly planted and watered, will begin new growth immediately and you will gain a whole summer's growth!

Note: Deborah Flower's experiment and recommendations are described in Pests of Landscape Trees and Shrubs, 2nd Edition, Publication 3359 of the UC Integrated Pest Management Program and available online at ipm.ucdavis.edu.

Written for the Davis Enterprise, June 28, 2007

Let Nature Run Its Course

2010-06-21T15:39:00.000-07:00

Letting nature run its course is a valid strategy for pest and disease management in the garden!

Reaching for broad-spectrum insecticides and fungicides is rarely necessary and often does more harm than good.
For example, there have been a lot of fungus problems on leaves of shrubs and trees during this wet spring, especially on roses.
Fungus disease symptoms show up when the pathogen, the host, and the environment interact to cause the disease to inoculate, establish, and spread. We are fortunate to live in a climate which is usually unfavorable to the continued spread of fungus. A couple of days of dry north wind can stop most diseases in their tracks. You can prune an infected plant to open it upÓ and allow better air movement; water early in the day to allow leaves to dry off, and make sure you have the plant in the right sun exposure. Roses in the shade, watered with sprinklers, and allowed to get overgrown are going to get a lot more disease problems than those planted in the sun, pruned properly, and watered at ground level.

As for aphids, there is outright warfare going on in your garden, though you'd practically need a magnifying glass to see it. Why poison the plants when beneficial insects are riding in like cavalry to the rescue?
Life as an aphid is actually pretty rough. When you get an infestation, it seems they have come out of nowhere. Indeed, a female aphid produces 50 or more babies a day, and each baby is a pregnant female. They NEED this massive reproductive capability because so many beneficial insects find them delectable: aphids are soft, succulent, and stuck in place.
Three beneficial insects that you can see readily are ladybird beetles (ladybugs), lacewings, and leatherwing beetles (aka soldier beetles). The larvae of the first two resemble little dragons, inching along on rose buds and plum leaves as they eat aphids. Ladybird beetles and leatherwing beetles fly around, roving rapidly over leaves and flowers.

The aphids that we see in summer are often naturally controlled by parasitoid wasps and by the larva of small flies.

Note: the terms parasite and parasitoid are similar. The difference is that a parasite usually doesn't kill the host, it just lives on it and takes nutrients from it (think tapeworms and mistletoe). A parasitoid lives on or in the host and ultimately kills it. The adult usually lives free of the host.

If you look closely at any population of aphids you are likely to see some that are tan, listless, and bloated. If so, you need take no further action: tiny parasitoid wasps (usually aptly named Aphidius species) have laid their eggs in some of the aphids. The larvae are feeding on the aphid from inside, getting ready to pupate and emerge and further decimate the population. Those that have emerged leave behind aphid carcasses with neat holes cut in them. After a slight lag, the population of wasps will catch up with the aphids. It is rare to see the adult wasps, and they can't sting you. These little wasps are everywhere; I rarely see a population of summer aphids that isn't being controlled by them.

You may also find very small worm-like larvae near the aphids. These are the progeny of tiny flies called aphid midges (Aphidoletesspecies). Each midge has strong jaws and eats several aphids before pupating. Apparently they like to hunt: they often kill many more aphids than they eat. The problem is, the adult

Achillea 'Apple Blossom'
You can plant flowers to attract and keep beneficial insects in the garden. Plants that have small flowers in clusters provide nectar and pollen for small insects. Members of the carrot and daisy families are especially good. Shown here is Achillea Spring Blossom, one of many garden hybrids of Yarrow. Yarrow has fern-like foliage, summer-long clusters of flowers, and is very easy to grow in sun or light shade.

These beneficial insects don't just eat pests. The adults need food and water too. Small areas such as shallow stones or abalone shells where sprinkler water can puddle can provide moisture. Honeydew from the tiny flowers of annuals such as Sweet alyssum draw and feed many beneficials. Any flowering plants in the carrot family (Umbelliferae), including cilantro, fennel, parsley, and Queen Anne's lace will help attract them. Members of the daisy family provide pollen, which many feed on. One of the best is yarrow (Achilleaspecies and hybrids), an easy perennial with showy clusters of tiny flowers, known to attract many types of beneficial insects. Yarrow spreads readily and is very long-lived, tolerating full sun or light shade and some drought.

You can plant flowers and create habitat for natural enemies. Or you can apply poisons with unintended consequences. The choice seems simple to me!

Click on any picture for a larger view!

Aphids under attack!
Aphids are common in early summer on landscape shrubs. Shown here on a leaf of Pittosporum tobira, the aphid on the left has been mummified and has larva of a small wasp (Aphidius species) inside it. The one to the right is healthy -- for now. The aphid at the bottom of the photo is about to meet its demise at the hands (or jaws) of an aphid midge larva (undetermined, but probablyAphidoletes species).

Some beneficials

Ladybird beetle on a rose bud
The common ladybird beetle is an effective aphid eater. "Ladybug" is the commonly used name, but they are actually beetles, not bugs. Learn to recognize the larvae, which look like little black and orange dragons. Plants with accessible pollen and sources of moisture can help keep ladybird beetles in the garden.

Young praying mantid on a Dianthus
One of the best-known beneficial insects is actually one of the least effective for pest management. Praying mantids are general feeders, so they eat pests and other beneficials (including each other) alike. However, they are fun to watch in the garden and are part of a healthy yard. Shown here is a young mantid on a carnation flower in early June; by now it has probably doubled in size.

Leatherwing (soldier) beetle

Canada bans Weed'n'Feed lawn products!

2010-06-15T12:21:00.000-07:00

Health Canada's Pest Management Regulatory Agency (PMRA), which regulates pesticides in that country, has announced the end of registration and legal sale of fertilizer/pesticide combination products in Canada, effective at the end of 2010:

"The PMRA, in conjunction with Canadian Food Inspection Agency, is taking action to uncouple the fertilizer-pesticide combination products intended for lawn and turf uses. A date of last sale of 31 December 2012 for fertilizer-pesticide combination products for lawn and turf uses has been set in order to allow for replacement products to be made available where needed."

The most common combination is fertilizer with a broad-leaf weed killer, usually 2,4-D and other similar herbicides.

"Turf fertilizers will continue to be available for broadcast application when needed. Pesticide-only products will also continue to be available for lawn care use to homeowners and commercial applicators for either spot treatments of localized weed patches or for use as broadcast applications to severely infested turf areas when warranted."

Link here

We get questions....garden problems in May!

2010-05-28T23:01:00.000-07:00

An odd year?!?

What's up with this weather?

2010: a strong El Niño year!

weather

climate

My peppers aren't growing!

An overview of early-season vegetable problems:

Virus or weather?
Too soon to tell.

The leaves of my roses are ugly!

The major rose diseases are:

For more, plus pictures, click here

Written for the Davis Enterprise, May 27, 2010

Bayer Advanced Fruit, Citrus, & Vegetable Insect Control -- a good idea?!?

2010-05-21T13:05:00.001-07:00

“I’ve heard there is a new systemic insecticide for vegetables and fruit trees.”
Yes, indeed: Bayer CropScience has introduced Bayer Advanced™ Fruit, Citrus & Vegetable Insect Control, which you pour on the ground around edible crops. It goes up into the plant and kills insects that are feeding on the plant.
My god, what a terrible idea!
“Keeping your plants protected from listed damaging insects has never been easier.”
Just because you can do something, doesn’t mean you should!

The active ingredient imidacloprid (Merit) is a widely used neo-nicotinoid systemic insecticide. We recommend it for control of some pests on ornamentals, in situations where you and bees won’t be exposed to it, and it is useful on houseplants. It is the active ingredient in a popular flea control product on pets. It is heavily used on some agricultural crops in California, including head and leaf lettuces and citrus, as well as on turf and ornamentals.

I understand the basic principle of toxicology: the dose makes the poison. How toxic a material is depends on how much you ingest. There are doses that are considered safe for humans. Neonicotinoids are especially toxic to insects and much less so to humans. But the regulatory agencies base their safe dosage on assumptions about our current intake of the product by other sources. You are ingesting imidacloprid regularly when you eat conventional produce, walk across commercially-maintained turf, pet a cat that has been treated with Advantage®, etc.

Ok, so you put this insecticide on the ground, it is taken up by the roots, goes up into the plant and kills anything that sucks or chews on the plant. Then it breaks down steadily in the plant over time. Apparently Bayer and various regulatory agencies believe that it’s ok for you to eat whatever the plant produces because it has diminished to less harmful levels in the plant.

This all assumes you follow the label instructions for the rate per square foot, that you only apply it once a year, and that you wait the specified interval before harvest. Why, one wonders, is it a 21 day waiting period for lettuce, but a 45 day waiting period for Swiss chard?

You can download the 10-page label from bayeradvanced.com. Read about imidacloprid at the cooperative-extension maintained site http://extoxnet.orst.edu/

Here’s what anybody selling, buying, or using this product needs to know:
• You must carefully follow the rate of application per square foot of garden space.
• The product is in the plant, including the part you consume. If it provides “Season-Long Protection!” then it is in the plant all season. Including when you harvest.
• It is important to check the interval before harvest for a particular crop, which ranges from 14 to 45 days after application.
• You cannot use this product more than once a year. In California we have two full vegetable growing seasons.
• Imidacloprid is very toxic to bees of all kinds. Bees are exposed to it through pollen.
• You should not apply it when trees are blooming or bees are foraging nearby. It can be taken up by the roots of nearby flowering plants. Your garden needs to be entirely separated from plants that bees might visit. Sub-lethal doses to bees have unknown effects. It is one possible factor being reviewed in Colony Collapse Disorder, but has neither been ruled in or out as a cause.
• It is very toxic to earthworms.

I am concerned that the manufacturer and the regulatory agencies have not considered California’s unique gardening climate.

I don’t know if the baseline for acceptable “average” intake from other approved uses has been updated since the mid-1990’s (that is the only data I could find online). There have been many new approved uses of imidacloprid in the last decade, including urgency permits for new pests. Imidacloprid is the pesticide of choice for many of the new pests that arrive in California, so I would guess that we are consuming more and more of it.

I personally would not use it or sell it for edible crops, and urge nursery professionals, Master Gardeners, and landscape gardeners to discourage its use.

Fungus weather!

2010-05-11T11:57:00.000-07:00

Rain every week is leading to many disease problems. Here is a chart that reviews some of the common diseases we've been seeing at the nursery recently. I have been removing specific fungicide recommendations from my articles, as availability of specific products has changed. In most cases fungicides aren't necessary, application is impractical, and oftentimes labeled products really don't work.

Good news: hot, dry weather stops the spread of most diseases. And one thing we can count on in the Sacramento Valley is that we will eventually get hot, dry weather!

Chart of spring diseases

Real Gardeners Plant Biennials

2010-04-27T19:34:00.000-07:00

I once heard that the gardening terms most misunderstood by beginning gardeners are annual and perennial. So let's review: an annual is a plant which grows, blooms, and dies within one growing season. Or, as the cynics put it, "a plant which should have bloomed before it died." A perennial is a plant which grows and blooms year after year.

Perennials may be herbaceous (soft), dying to the ground but resprouting. Or sometimes we call flowering shrubs such as lavenders perennials, and they are classed as woody perennials. Terms in horticulture often derive from how we use the plant, so there can be overlap between categories such as shrub and perennial.

So an annual flower blooms right away. Perennials bloom year after year. But what are biennials? These are plants which grow one season, bloom the second, and then die. They require patience and planning. They require replanting, although many reseed (some prolifically!). Hence they are plants for devoted gardeners.

So why do we grow them?

The long period of growth while the plant prepares to bloom allows it to store energy and develop large, complex flower structures (the structure that holds a number of flowers is called the inflorescence). In some cases they develop a large root to store water and energy, helping to support rapid elongation of a flower spike. When they finally bloom, biennials do it in a BIG way.

The common characteristics of biennials are:
o late season growth at ground level;
o continued growth in spring;
o late spring and summer bloom, often with very large, showy flowers on tall spikes;
o significant seed production;
o seedlings emerging again in late summer and fall.

This cycle has unique adaptive features. The low growth habit during the initial phase allows the plant to survive frequent mowing or grazing. The later bloom season means there is little competition from winter and spring grasses. Production of large amounts of seed has obvious advantages - for the plant.

Unfortunately, one of the most noxious weeds in California has found this biennial growth cycle very adaptive. Yellow starthistle sprouts in fall, forming a tight clump (rosette) of foliage at ground level. The plant forms a tap root with winter rains, which can grow deeper than the competing roots of nearby weeds and grasses. Leaves on the rosette grow steadily through the winter and spring, with the plant nestled at the base of tall grasses. Then, as the grasses dry off, get grazed, or get mowed to prevent fire hazard, the starthistle rapidly sends up bright yellow thistle flowers and goes to seed.

Starthistle is very prickly and irritating, is toxic to horses, and now is estimated to have spread to over 15 million acres in California (up from 8 million in the mid-1980's, according to the Weed Research and Information Center at UC Davis). A field of starthistle is basically impenetrable on foot or horseback. On the plus side, the flowers are pretty and bees like it.

Many biennials require a cold period (vernalization) before they initiate flower buds. So they are planted in fall for blooms the following spring or summer. As with starthistle, during the initial season they develop a rosette (a tight complex of buds and leaves at ground level, densely packed along a short stem). Once they've had their period of chilling, longer days initiate flower development. The flower structure (inflorescence) elongates and produces dozens, sometimes hundreds, of flowers. Those flowers may set prodigious quantities of seed. Let's just say that your patience is rewarded.

Warren Roberts, retired Superintendent of the U.C. Davis Arboretum, credits an unusual biennial for sparking his interest in plants. He remembers the Tower-of-jewels in a neighbor's yard from early childhood. Echium wildpretii (native name tajinaste rojo) certainly follows the biennial pattern. In the first season you get a mound of silvery foliage, resembling Cousin Itt from the Addams Family. Then in late spring the plant begins to stretch upward, and upward, and upward, ultimately to 7 to 8 feet or more! It was just such a flower spike poking above the neighbor's fence that attracted young Warren's attention, intriguing him with its Dr. Seuss-like qualities and launching his long career in horticulture.

All along the Tower-of-jewels flower spike are hundreds of small, showy flowers in a vivid hue of pinkish-purple. Hummingbirds and bees love all members of the genus Echium. After the long season of bloom thousands of seeds are produced. Even with a low germination rate, you are pretty likely to have seedlings. Tower-of-Jewels is native to Tenerife, one of the Canary Islands, which is a mild-winter area. We sometimes get frost damage on young Echium plants here, but they pull through and bloom.

Biennials we grow for their flowers include some very old garden favorites.
o Canterbury bells (Campanula medium) are planted in partial shade, producing lavender or white cup-and-saucer flowers in late spring. The big, fleshy plants flop over easily. Stake or cage them!
o Dollar plant (Lunaria annua) can grow in full sun to considerable shade. The pretty purple flowers are followed by thin, papery seed capsules that are shaped like coins. The seed capsules are often dried for flower arrangements. I have this plant re-seeding around my property, but not to the point of being invasive. As I was photographing it at night (for better contrast) I discovered that the flowers have a sweet scent in the evening.

o Evening primrose (Oenothera species) is best known for the pink-flowered Mexican species that is used as a ground cover. But the genus has many biennial species. Mostly adapted to desert areas, their flowers open in the evening for moth pollination. Some are quite invasive reseeders. My mother planted O. biennis in her cactus garden in San Diego, and then spent many years digging out seedlings.
o Foxgloves (Digitalis species) and Hollyhocks (Alcea rosea) are probably the best-known biennials. Foxgloves can grow in considerable shade, as well as sun. Although there are now annual varieties of foxglove such as 'Foxy' which bloom the first year from seed, most are biennial or short-lived perennials. Hollyhocks love sun but can tolerate some shade. Both bloom in late spring and well into the summer, with flowers continuing to open along the spikes for many weeks. If you aren't too fastidious about your garden, and don't mind the spent bloom spikes falling over into the border, both will reseed freely.
o Sweet William (Dianthus barbatus) is perhaps one of the most fragrant biennials, possibly one of the most fragrant garden flowers ever. The genus Dianthus includes carnations and pinks, and the scent of Sweet William is similar but even more pungent. Largely superceded by modern Dianthus cultivars, Sweet William is still grown by old-fashioned, patient gardeners like me. It comes in dwarf (6 inch) and tall (12 inch) forms. Hard to find in garden centers, the seed is easy to save and plant from year to year.

There are many edible plants whose biennial habit we exploit, growing for part of the lifecycle and consuming the root or tight rosette that the plant was developing for its flowers. Beets and carrots develop roots in fall and winter, which we eat before the plant has a chance to flower. Cabbage and Brussels sprouts, celery, lettuce, and parsley form heads which, if not harvested, would bolt and flower the next spring (if that happens, leave the blossoms; they attract beneficial insects). If you plant parsley, expect it to flower and go to seed in the second year, and then die. So gardeners generally replant it each year to have a steady supply.

In addition to Yellow starthistle, another invasive biennial is worth noting. Dames Rocket (Hesperis matronalis) is an attractive plant that was introduced by the pilgrims in the 1600's (I guess that would make it simultaneously an heirloom and an invasive!). Each plant sets very large quantities of seed. It is often included in "wildflower" seed mixes, and has spread to nearly every state. It resembles Money plant (above) which is not considered invasive and would be a better choice for gardeners.

Plant biennials for future enjoyment! These old garden favorites have many advantages that reward your patience.

For pictures and more: http://redwoodbarn.com/DE_biennials.html

Written for the Davis Enterprise, April 22, 2010

Target Corp closing all of its garden centers

2010-04-20T11:40:00.000-07:00

From Grower Talks:
Target Closes Garden Centers
| Chris Beytes
>> Published Date: 3/15/2010

http://www.ballpublishing.com/GrowerTalks/ViewArticle.aspx?articleID=17661&highlight=target+garden+center

Take a good look at this Target garden center in Merritt Island, Florida, as it’s the last you may see: The big-box retailer announced in March that it’s closing its remaining garden centers in Florida, California, Arizona and Nevada and getting out of garden centers altogether, effective late September. The move affects more than 260 stores.  

Why? “Several reasons,” answers Target spokesperson Jana O’Leary. “First is that the garden centers don’t provide significant value to our guests. Also, it’s no longer a profitable business for us.”

When asked if they would continue to sell garden hardgoods inside the store, such as potting soil and fertilizer, Jana replied that they’d continue to do that this season, but she couldn’t confirm if they’d continue inside L&G sales beyond 2010.   She also couldn’t confirm whether or not they’d continue to sell poinsettias and other holiday crops inside the stores. However, GrowerTalks has heard that they have committed to growers for poinsettias for 2010. Until September, they will continue to operate “business as usual throughout the entire spring and summer seasons,” she says.  

You can’t talk about Target without talking to Ken Altman of Altman Plants, headquartered in southern California. He estimates they provide 85% of the plants to Target’s garden centers—so it’s a major blow to his business. Still, Ken seemed to be taking the loss of a major customer philosophically.

“You know, you never want to take a hit like this,” he says, “but we’ve had a really, really great relationship with Target since the mid ’80s. They’re a great company. They’ve been great partners. They’ve worked with us on programs and they’ve always been open to our creativity. Even something like this, they gave us eight-nine months notice to adjust.”  
Ken says his focus now is finding other ways to use his production capacity, to save as many jobs as possible for his employees. GT

Caveat emptor!

2010-04-10T13:25:00.000-07:00

Planted too early?! The retail conundrum.

A nice young lady came into my nursery yesterday. She moved to California this year and is new to gardening here. Seeing vegetable plants at a large retailer in March, she purchased and planted the whole range of summer vegetables. Now she wanted my advice about what was going wrong, which was pretty much everything.

She planted in March: beans, corn (from six-packs), eggplant, melons, peppers, squash, tomatoes.

Like many customers nowadays, she brought me digital pictures of her garden. Nothing is growing at all. Pests are eating the leaves of the young seedlings. Leaves of the squash are curled and distorted. The corn is blowing over, not growing. All the plants look yellowish.

We discussed possible strategies for the snails and earwigs that are eating the seedlings. But I had to tell her that the basic problem with all the plants is that they were purchased and planted too early, in soil that is too cold, with night temperatures much lower than these summer vegetables prefer.

Let’s review those symptoms:
• Pest damage
• Curled, distorted leaves, burnt on the edges
• Plants blown over, bent at the stem by wind
• Leaves yellowing
• No new growth.

Although I now have gained a long-term customer, she was dismayed to learn that a store was selling plants at an inappropriate time. I try to be diplomatic in explaining the purchasing and marketing practices of these large retail chains. But the fact is that the large retailers have no disincentive to sell plants out of season. They don’t really even have buyers for their garden departments anymore: the plant materials are mostly chosen, delivered, and displayed by the wholesale growers. The growers take all the risk.

Only very large growers can produce enough material to supply the big-box retailers. It is possible that these plants were appropriate in warmer parts of their delivery range, such as Southern California. But there is no feedback process telling them that summer vegetables are inappropriate in retail stores in central and foothill regions of Northern California in March.

Thanks to guaranteed sale and pay-at-scan arrangements with the growers, the retailer doesn’t pay for anything until it is actually purchased. If it dies in the store or doesn’t sell, the grower absorbs the cost. Apparently, these large growers consider it worth the risk. Why? Because unsuspecting novice gardeners will purchase the plants, thinking (reasonably) that if it is in the store, it must be planting time.

Yes, certain large retailers “guarantee” their plants. A plant guarantee is a great marketing ploy, since hardly anybody ever returns a plant. Sales staff aren’t going to discourage the early sales. So caveat emptor: let the buyer beware.

I suppose this is all of some benefit to independent garden stores, for the small number of gardeners who find their way to us to get advice after they plant. But what about the ones who get enthusiastic about gardening, then get poor results and give up? Is this beneficial for the industry as a whole? How many plants get thrown out after being delivered hundreds of miles from the growing ground?

Here’s the basic info:
Plant tomatoes when night temperatures are 50 degrees F or above. Usually that is late April in Northern California’s central valley. That is when we plant beans, regular sweet corn, potatoes, cucumbers and summer squash.

Plant peppers and eggplant when night temperatures are 55 degrees F or above. Usually that is May. That is when we plant lima beans, cantaloupe, extra-sweet and white corn, okra, pumpkins, winter squash, and watermelons.

There’s no hurry. We have a very long growing season, extending through October most years. Summer vegetables can be planted well into June or even July in some cases.

It’s ok to buy the plants early if you see varieties you like. Just keep the pots in a warm place and keep them watered. Transplant them into the next sized pot if they are root-bound. Container soil will warm up and keep the roots warm. Raised beds warm up ahead of garden soil, so you can plant in those beds a couple of weeks before you would out in the open ground.

It's Too Early!!!

2010-03-14T03:14:00.000-07:00

Too chilly to plant tomatoes, peppers, and eggplant?

When do we plant summer vegetables?
The soil needs to be warm!
Night temperature can be a guide to how warm the soil is.

Night temperature and soil temperature guidelines:

Tomatoes
Night temp: 50 – 55F Soil temp: 60F

Peppers, eggplant
Night temp: 55 – 60F Soil temp: 70F

For night temperature: use a maximum-minimum thermometer, or check the local weather listings.
For soil temperature: use a soil thermometer, or visit the UC Davis weather info site.

Going by the calendar: usually mid to late April for tomatoes, early May for peppers.

Why do nurseries and hardware stores have them now?
Some gardeners like to buy small plants to shift them into larger pots for a few weeks before setting them out.
Everyone else is selling them, and we get tired of saying "it's too early!"

What happens if we plant too early?
Tomatoes will sit, discolor a bit, and then begin to grow as it warms.
Peppers and eggplant will sulk and be stunted all season. Peppers planted later out-perform peppers planted early.
To increase soil temperature:
turn in organic material and mound up the soil.
build a raised planter bed
cover the area with seedling blanket

Or, just wait! We'll have plenty in stock through June!

A new pest in fruit trees!

2010-02-26T09:39:00.000-08:00

Spotted Wing Drosophila
A new pest in fruit trees; homeowner information for monitoring and control of Spotted Wing Drosophila (aka Cherry Vinegar Fly).

Serious infestations in the ripening fruit of cherries were reported in several counties of Northern California, including Yolo County, in spring 2009. Fruit were full of squirming larvae. Most scientists, nursery professionals, and master gardeners encountering the pest simply assumed it was a regular fruit fly infesting overripe fruit. Home gardeners protested that the fruit was ruined right on the tree, just at the peak of harvest. Locally our first reports came from South Davis. Damage to cherries in Santa Clara County was so severe, especially on early varieties, that growers had to stop harvest.

Photo by Ed Show, courtesy of UC Cooperative Extension, Santa Cruz County

State entomologists had to search to identify this new pest, eventually finding a description from Japan from the early 1930's. The spots on the wings of the male flies clearly marked it as Drosophila suzukii. You know Drosophila as "fruit flies," the annoying little flies that hover over rotting fruit. Some in that group are called "vinegar flies." The new pest was initially called the Cherry Vinegar Fly (CVF), but cherry growers weren't thrilled about that name. So it is now called the Spotted Wing Drosophila (SWD).

The homeowners were right: unlike most fruit flies, which infest overripe and rotting fruit, the SWD adult lays its eggs in fruit that is just ripening, and the larva hatch very quickly in warm weather. Damage can be first seen as a small depression on the underside of the fruit, where the adult female has oviposited (laid her eggs). Larvae hatch and begin to damage within as little as two days.

Photo by Larry Strand, courtesy of UC Statewide IPM Program.

Since then, infestations have been found in California in blueberries, blackberries, olallieberries and raspberries, plums, nectarines, and strawberries. Wine and table grapes have been found infested in Oregon, but not yet in California. The original paper describing infestation in Japan in 1939 listed apples, peaches, and persimmons. You can expect possible infestations in nearly any type of soft fruit that ripens in warm weather. Cherries, strawberries, and blackberries have been the main concern so far.
There isn't going to be any quarantine or regulatory action taken, because the fly is already well established and distributed widely in California, as well as in several other states. Fruit flies disperse very readily, helped along by humans.

The lifecycle of this pest
They apparently overwinter as adult flies. While many will die at freezing temperatures, the whole population won't be killed and enough survive to repopulate. The female lays 2 - 3 eggs per fruit, about 350 in her lifetime, and they can have as many as 10 generations per year (perhaps 3 generations in the course of a cherry crop).
They are most active at 68 degrees F, and activity is reduced at higher temperatures; in fact, the males become sterile at 86 degrees F. So the greatest threat is to fruit that ripens in spring and early summer. Vinegar flies in general are very sensitive to desiccation, and will die within 24 hours in the absence of water. Irrigation management may be part of an overall pest reduction strategy: keep the orchard floor clean, and avoid moisture on the ground and nearby weeds while the fruit is ripening.

What are we going to do about this?
When a new pest arrives, plant professionals have a problem. We can't recommend a pesticide if it isn't labeled for a particular pest and crop. Working with cooperative extension personnel, commercial growers can get emergency permission to use products based on efficacy data from other states, if necessary. Similar recommendations may be forthcoming for homeowners. But at the moment nothing is labeled for you to use on this pest in California.
If you didn't have a problem last year, you can monitor to see if the fly is present in your garden. This is easy, because fruit flies are attracted to vinegar, rotting fruit, sugar, and yeast. Mason jars or fly traps filled with homemade bait solutions can be hung in trees. According to one reference, "yeast and sugar mixed with water proved the most effective bait (one package of Baker's yeast, four teaspoons of sugar and 12 ounces of water)." You will surely catch all kinds of interesting insects, including many species of Drosophila!

Traps can be made readily from materials at home; it's pretty easy to attract and catch fruit flies! Mason jars or Rescue Fly Traps can be filled with any number of vinegar or sugar solutions. Options include a mix of yeast and sugar, or yeast with banana slices, or just an inch or so of apple cider vinegar. In field tests, the yeast/sugar mix caught the most flies. Trapping can be part of an overall management strategy.
Mary Louise Flint, Extension Entomologist with the UC Statewide IPM Program, and author of numerous publications on integrated pest management, questions whether trapping will be worthwhile for home gardeners. Commenting by email, "The problem with trapping flies is that you get so many different flies and potentially hundreds in each trap and they all become a sticky mess. You will likely get hundreds of regular Drosophila (and many other species) in your traps and it will be difficult for home gardeners to separate out the few SWD that may be there." She points out that "by the time you find the flies in your traps, it may be too late to apply" control sprays.
Suffice to say, you would need to check your traps often, learn to recognize this fruit fly. The male is the only species with a spot on the wing, and the female has a huge ovipositor. Spray immediately if you find any. Or just watch for damage on your earliest varieties; look for the dimple-shaped spot on the fruit where the eggs are deposited. Sprays could protect later-ripening varieties.

What control measures are available?
When this pest arrived in Washington State, cherry orchards quickly reached very high levels of infestation. Fruit full of squirmy worms have little market appeal. Tests of conventional pesticides such as malathion gave good results, but full tree coverage was necessary and control required 3 applications at 5-day intervals. In my opinion, spraying your ripening fruit with a commercial pesticide sort of defeats the goal of healthy home-grown produce. And without a commercial sprayer, you won't get good coverage, so results will be spotty.
Spinosad, an organic spray with very low human toxicity, was equally effective when applied the same way. But when it is mixed with a bait to lure the flies to the spray droplets, they got very good results just spraying coarse droplets more or less into the middle part of the tree. That is something homeowners could do with a small hand-held sprayer. Spinosad itself is readily available in garden centers. Monterey Garden Insect Spray and Green Light Lawn & Garden Concentrate are 0.5% spinosad. The key is the bait attractant, which those products lack.

What is spinosad?
It is a byproduct of fermentation of a soil bacterium that was found in an abandoned rum distillery in the Caribbean by a scientist who was on vacation (and my kids used to complain about being dragged to botanical gardens!). It has very low toxicity to mammals.
There is one product called GF-120 NF Naturalyte that mixes spinosad with a bait attractant. Unfortunately, it is only available from farm chemical supply companies, and only in gallon bottles at about $155.00 - not a likely option for someone with a couple of backyard trees! GF-120 is a safe, organically-approved spray, so I was curious what bait attractant they were mixing with the spinosad. The label isn't very informative; chemical companies tend to be a little proprietary about their products. But every chemical has an MSD sheet, which lists all the precautionary statements, the handling instructions, etc., for each ingredient; by law, that must list each active ingredient. Lo and behold, the bait is propylene glycol. When I mentioned this to my son, who works with cars, he arched his eyebrows. "You mean antifreeze?"
Yes, propylene glycol, which you know as auto coolant or antifreeze, is very sweet to the taste (pets get poisoned by antifreeze leaks from vehicles) and attracts fruit flies. Apparently it can be produced in an organically-accepted manner. It is even a food additive. GF-120 is 2.5% propylene glycol, which acts to draw the fruit flies to the spray droplets, where they feed and are killed by the spinosad.

Sweeten the pot?
The principle of adding sweeteners to pesticides is a little unorthodox, but not unprecedented. I was reminded of a similar extension-approved tactic we used years ago. Back when we had a commercial pest-control service, we did spraying for walnut husk fly. A farm adviser at the time recommended adding Karo corn syrup to the spray tank! Current recommendation for husk fly is to "add about 4 - 6 tablespoons of molasses per gallon of water applied," and spinosad is now the spray of choice for that (unrelated) pest.
Perhaps the same idea could be adopted for homeowners seeking a reasonable control for Spotted Wing Drosophila: use spinosad at the label recommendation, with 4 - 6 Tbsp of molasses per gallon added to the sprayer.
Use a coarse spray on the trunk and interior of the tree, to draw the flies away from the fruit. You could even use a small squirt bottle and just spray around the inner canopy of the tree. Do this a few days before the fruit ripens, and again once or twice as it begins to ripen. Molasses is going to be sticky, so wash your sprayer out with detergent after use. Spinosad on the fruit will not hurt you, but it isn't necessary to spray the fruit.

It's important to note that GF-120 is the only pesticide extension personnel are currently suggesting, as Flint commented to me, "but with the caveat that it may not be completely effective and is also difficult to obtain." Spinosad with molasses might work for home gardeners, but "we don't have any data for backyard trees." Extension folks and nursery professionals will be interested in any results from home gardeners. If and when a labeled product is available in a smaller unit, at a reasonable price for homeowners, it would be best to use that. We'll keep you updated.

Another option will be to pick the fruit while it is still firm, bring it inside, and ripen it indoors. Look closely at the fruit for the dimple-like point where the female deposits the eggs. Or just sort through your fruit at harvest. Infested fruit is very recognizable: it turns to a pulpy, wormy mess almost instantly.

For more photos and links, check out the original article at http://redwoodbarn.com/DE_Drosophila.html

Written for the Davis Enterprise, February 25, 2010

Blueberries?

2010-02-08T10:44:00.000-08:00

Growing acid-loving plants

Written for the Davis Enterprise, December 24, 2008

February 7, 2010: A great article in the Sacramento Bee prompted a flurry of phone calls to our nursery -- can we really grow blueberries here? Here are the issues for gardeners in Davis, Woodland, Dixon, and other communities that rely on groundwater for irrigation. Water from wells is hard and has a high pH.
Oh, those acid-loving plants.

Camellias are the queen of the winter garden - in Sacramento. Azaleas mean spring. Can we grow blueberries? How about true blue hydrangeas? What does "acid-loving plant" mean, anyway?
The issues with Davis water.

What's the problem?
Water in Davis and Woodland is alkaline, meaning it has a high pH, which causes deficiencies of some minerals essential for green leaves and plant growth. When the leaves are yellow between the veins, the plant is deficient in iron. When that yellowing is blotchy, it is lacking magnesium. When the new leaves are smaller than they should be, it is lacking zinc. The water is high in certain salts, which can cause ugly burnt edges on the leaves of some plants.

Note: it isn't always pH that is the problem. Overwatering can damage roots of plants, so they can't take up the minerals. When we see deficiencies on common landscape shrubs such as Escallonia and Nandina, we suspect overwatering.
What are these finicky plants?

Group 1: we can grow these with special soil amendments and additives. If you don't fertilize them regularly and/or treat the soil with pH reducers, they will get anemic and fail to thrive.

o Blueberries
o Camellias
o Gardenias
o Hydrangeas (more on flower color below)
o Lesser-known ornamentals include Loropetalum and Pieris
o Some specialty conifers: Cryptomeria, Chamaecyparis
o Azaleas can get chronically anemic and are prone to crown rot, but may be successful for a couple of years.
o Japanese maples (Acer palmatum) prefer acidic soil conditions, but most of the leaf damage attributed to our water on these small trees is actually caused by hot, dry summer weather.

Group 2: these shrubs and trees often show persistent deficiencies.

o Deciduous magnolias: Saucer magnolia (M. soulangeana), Star magnolia (M. stellata), and others. Deficiencies are common but correctible, and these are worth growing for the showy spring bloom.
o Citrus and rose leaves often show iron deficiency, and sometimes show magnesium and zinc deficiency.

Group 3: chronic deficiencies and leaf burn make these plants ugly. Not recommended.
o Dogwood (Cornus florida). Some species of Cornus grow here, but not these showy-flowered types.
o Rhododendrons.
o Sweetgum (Liquidambar styraciflua) and Sour gum (Nyssa sylvatica, also called Tupelo).
Soil chemistry: what's going on?

It isn't that the important minerals aren't present in the soil. Adding more iron, magnesium, or zinc won't correct the problem. As the soil gets more alkaline, they become insoluble.
One example. Iron is taken up by plants as a positive ion (Fe++) via ion exchange on the root surface. Hydroxide (OH-) is more abundant in alkaline soil. Hydroxide combines with the iron ions the plant needs, creating iron hydroxide (Fe(OH)2) - which the plant can't absorb.

Well-meaning gardeners can make the problem worse by applying too much fertilizer, or the wrong type. For example, excess phosphorus can make iron unavailable, and vice versa. It's easier to correct the soil pH than to try to add a specific mineral. Transplanted east-coast gardeners need to know that since lime raises soil pH, we don't apply it here at all.

So, what to do?
Make the soil more acidic. The technical term is to acidulate the soil.

Applying sulfur is the simplest way to go: elemental sulfur will react with soil microbes to produce sulfuric acid and hydrogen. While this happens fastest during warm weather, it's ok to apply sulfur any time of year.
For acid-loving shrubs and trees, add a couple of cups of soil sulfur to each planting hole, mixed thoroughly with the backfill soil at the time of planting. When treating an entire bed, apply 5 - 10 lbs. per 100 sq. ft. Mixing it in to the soil increases contact with the microbes, giving faster results than broadcasting it on the surface. Then to follow up, broadcast granular sulfur around established plants each season. Raking it in, or covering it with mulch, gets the soil microbes working on it faster.

Many fertilizers contain sulfur, indicated by the "sulfate" in the name or in the list of sources on the guaranteed analysis. Each has special uses, as well as possible drawbacks.
o It takes 8 times as much iron sulfate to achieve the same results as soil sulfur.
o Aluminum sulfate (used to turn hydrangeas blue), if used in large quantities, can lead to an excess of aluminum which can cause other nutrient deficiencies.
o Ammonium sulfate packs a wallop of nitrogen due to the ammonia content; this inexpensive lawn food, misused, has fried a lot of lawns via overdose!

Synthetic fertilizers labeled for acid-loving plants get most of their important nutrients from sulfate-based sources. Cottonseed meal is an excellent organic fertilizer that makes soil more acidic.
Adding organic material (i.e., compost) makes minerals available to plants by an indirect route. Decomposition of organic material creates humic acid, which loosely binds (the technical term is chelates) those important positive ions of iron, magnesium, etc., making them available for the plant roots. The humic acid keeps the iron and other ions from precipitating out into those insoluble forms.

So to counter the effects of a summer of watering with our hard alkaline water:
o You want the soil around the roots to be providing sulfuric acid and humic acid. Both of these are created slowly but steadily during warm weather when there is sulfur and organic material mixed in the soil.
o Additional sulfur and mulch can be put on the surface around established plants. Scatter sulfur and add a couple of inches of bark mulch each spring or summer.
o Leaves and pine needles can be spread around the plants in fall to decompose.
o Fertilizers containing sulfates can be applied per the package instructions during the growing season (read the label!), but don't rely exclusively on them to lower soil pH.

Miscellaneous remedies.

Weak vinegar solutions, and epsom salts (magnesium sulfate) are sometimes used, providing short-term correction to the pH. Some soil amendments are naturally low in pH: peat moss is widely used when planting camellias and azaleas, though it is a little pricey here since we are far from the peat bogs. Coffee grounds are helpful.
How about avoiding the hard water in the first place? Collecting enough rainwater to provide for a whole season isn't very practical, unless you build a cistern.

Toxicity: boron.

Boron gets blamed for a lot of the problems caused by high pH. "You can't grow camellias in Davis because of the boron!" Well, no: we can grow camellias with effort, and it is mostly just the alkaline water supply that is the problem. Boron is not our primary problem here.
Natural borax deposits in the soils of the coastal mountain range erode and dissolve into the creeks that replenish our ground water. Plants require boron in very small quantities, but it is toxic to some plants at high levels. It doesn't help that many fertilizer manufacturers, trying to include everything plants might need, add boron!

Boron passes readily through the plant and accumulates in the leaves. It takes a couple of years for the boron to build up in the leaf to toxic levels, so deciduous plants drop their leaves before any damage is visible. The most common toxicity symptom is black edges on older leaves of certain broad-leaved evergreens; for example, on evergreen Magnolia (M. grandiflora) and strawberry tree (Arbutus unedo). It's ugly, but not harmful.

What to do?
Boron is soluble. Water deeply and thoroughly. I know, I know: the water you are using contains more boron. But the problem results from shallow waterings, as from a drip system, leaving a buildup of boron salts in the root zone. These salts are often visible on the edge of the watering zone. A good long soak dissolves a bunch of that boron and carries it past the root zone. So does winter rainfall.

What's the deal with hydrangeas?
How does the soil make the flowers blue or pink?!

Ok, more chemistry. Some red and blue flower pigments have very similar chemical structures, and in the case of hydrangeas the molecule can undergo a reversible change in the plant based on the pH of the sap. When the soil around the plant's roots is alkaline, the plant sap becomes slightly alkaline, creating the pink pigment in the flower. When the soil is acidic, so is the plant's sap; the molecule sheds a couple of ions and becomes a different pigment - blue this time. If the pH is neutral, a different pigment is formed, this one mauve in color.

Because we are constantly watering hydrangeas with alkaline water here, it is a challenge to get the blue pigment in the plant as the flower buds are forming. Aluminum sulfate is used (in very small quantities) for this purpose because it causes a quick drop in soil pH. Sulfur added to the soil reacts too slowly to achieve the pigment change within a single season. Apply the aluminum sulfate as the shrub leafs out in the spring, and then again every couple of weeks until you see flower buds. Results vary.

Are there any plants that prefer an alkaline soil and water?
Plants native to arid climates tend to tolerate alkaline conditions. Many references indicate that lilacs also do, and they certainly grow well here.

City of Davis water quality reports are available online here
The pH of Davis water in 2007 averaged 8.3, Woodland 8.23. 7.0 is neutral, less than 7.0 is acidic, greater than 7.0 is alkaline.

Here is the Sacramento Bee article: http://www.sacbee.com/165/story/2516673.html

Heirlooms, or Hybrids?

2010-02-07T16:18:00.000-08:00

Heirlooms or hybrids?

Nearly every plum you buy is a complex interspecific hybrid between Japanese, Chinese, and sometimes American species. Luther Burbank spent more time on plum hybrids than any other plants, estimating that he reviewed 7.5 million seedlings. Many varieties that he introduced in the 1890's remain favorites today, including Santa Rosa, Satsuma, and Wickson. Shown above are some commercial plums grown in Chile, along with some Meyer lemons -- which are also probably hybrids, most likely between a true lemon and a mandarin.

Fruit Trees

www.slowfoodusa.org

Roses

Vegetables

A labor of love?

Bred and introduced by Floranova of the United Kingdom, the Angel (TM) violas are hybrids between pansies (Viola wittrockiana) and violas (Viola cornuta). Flowers are smaller than pansies, but hold themselves up better in the rain; larger than violas, with the abundant bloom of that species. Shown here is uniquely striped Angel (TM) 'Tiger Eyes'. Floranova also has operations in Costa Rica.

Helleborus orientalis, the Lenten Rose, is an easy-to-grow perennial that will bloom in full shade, in winter. For many years only seedlings in a limited range of colors were available, and the difficulty of propagation made the plants expensive. Heronswood Nursery began a breeding program, selecting for a wider range of colors and for two-toned flowers. After 13 years, the first hybrids came on the market. Shown here is 'Phoenix', an ivory white flower with a distinct pink edge. Photos courtesy of Heronswood Nursery.

Written for the Davis Enterprise, February 26, 2009

Starting summer vegetables from seed!

2010-01-28T15:31:00.000-08:00

When to plant

Read the whole article here

It's bareroot season!

2010-01-21T10:47:00.000-08:00

The Bareroot Season: the gardening year begins

I had the only European white birch tree in my neighborhood, and I hauled it home on the bus. When I was a teenager I got to choose a tree for my yard. My friends and I rode the bus downtown to Walter Andersen Nursery, the largest nursery in San Diego. January!

Bareroot season! There were bins of roses, fruit trees, and shade trees heeled into shavings. Deciduous trees aren't common landscape items along the coast of Southern California. Palms, Norfolk pines, and eucalyptus predominate. But the pictures of soft green foliage and clean, papery white bark enchanted me. I looked for the biggest tree I could buy with my gardening allowance and found a ten-foot tall birch.

The nurseryman yanked it out of the shavings, wrapped the roots, and rang up my purchase. Then he stunned me by whacking the top of the tree off. More on that later. The bus driver looked askance as we boarded, then decided to charge me an extra fare (25 cents) for the tree. Planted in the middle of my meadow (the former lawn, which I no longer mowed), my Betula pendula grew five feet a year, flourishing in the midst of all the subtropicals I had planted, looking about as out of place (and about as white) as the tourists at our local beaches.

Californians may be startled to learn that nursery plants in much of the rest of the country are grown in dirt, in fields, whence they are dug up and wrapped in burlap and wire for sale. Here most of our nursery plants start their lives in greenhouses and are then move into pots in specially formulated potting soils, sitting on clean beds of gravel. But deciduous fruit trees, many shade trees, and nearly all roses are still field grown.

The arrival of bareroot trees and shrubs in January marks the beginning of the planting season. Nowadays many nurseries pot the roses and fruit trees as soon as they arrive. But some still stow them in shavings or sand to sell for a few brief weeks before warm weather breaks the dormancy.

The sandy river-bottom soils on the east side of California's Central Valley are perfect for production of deciduous trees and shrubs. Growers plant the rootstocks a few inches apart, then graft or bud on the desirable fruit or shade varieties in spring. In a season or two, the tree is ready for harvest. As soon as the trees are dormant, specialized machines dig them up, sans soil (hence "bare root"), and teams of fieldworkers sort, stack, and bundle them. Within weeks millions of trees are being shipped all over the country and overseas for orchards and home gardens.

There are just a few major growers of bareroot fruit and shade trees in California. All produce large quantities of commercial varieties of stone fruits, pome fruits (apples and pears), and nut varieties for orchards, and each has found a special market niche. Based on figures from five growers, 8 - 10 million trees are grown and shipped annually. Take that, global warming! Some grow only for commercial orchards, but two split their product lines between orchards and home gardens. These are venerable businesses. The youngest, Sierra Gold Nurseries, is 58 years old; Fowler Nursery in Newcastle will be 100 years old in 2012!

Dave Wilson Nursery (1938) in Hickman (east of Modesto) sells specialty fruit trees, working to broaden the ripening periods and expand the fruit palette. Their collaboration with Zaiger Genetics has led to "150 or so" varieties, says former sales manager Ed Laivo (now retired): white and miniature peaches and nectarines, unique hybrids such as apriums and pluots (apricot/plum hybrids), a new nectarine/plum hybrid, and more. The name notwithstanding, Zaiger Genetics uses conventional hybridizing techniques (not genetic engineering), hand-pollinating and back-crossing and rigorously evaluating tens of thousands of seedlings.

What's new on the horizon? How about the peacotum? (peach - apricot - plum, rhymes with bottom.) Crosses between peach, apricot, and plum, Zaiger and Dave Wilson have test varieties "maybe to introduce in 2010, we'll see," says Laivo, adding that the flavor is "out of this world." Laivo is well-known in nursery and gardening circles for his tireless promotion of backyard orchard techniques, whereby home gardeners plant trees close together, prune severely to reduce fruit production, and do major pruning in summer for size control.

Field workers at L.E. Cooke Co. digging weeping mulberry trees. Photo courtesy of L.E.Cooke Co./Ron Ludekens.

L.E. Cooke Co. (1944) in Visalia grows fruit varieties as well as shade trees and ornamentals. A few years ago they pioneered a new training technique in field production of fruit trees: young trees are cut back once as they grow, leading to lower branching and easier access to the fruit. These EZ-Pick® trees have changed the look of what you buy: instead of an unbranched "whip" you can now get a shrubby, multi-branched plant. L.E. Cooke also grows many weeping trees: cascading varieties are grafted high up onto a rootstock to create unique garden specimens.

What is the advantage of bareroot?

What you get in the bareroot season is the biggest root system at the lowest price. The roots are so big, they have to be pruned to fit in containers. Properly planted and watered, a bareroot tree establishes faster than a container-grown tree. This is when nurseries have the largest selection of fruit tree and rose varieties.

Should I prune it?

No. The nurseryman I bought my birch tree from was old school; in the past bareroot trees were topped to "bring the tops and roots in balance." Research has found that the young trees establish better if the top is left unpruned at first. The more leaves you have, the faster the roots will grow. Pruning to train the tree can begin in the first winter after planting.

What do I do with this tree until I can plant it?

Keep it moist! The roots should be kept in moist shavings, potting soil, or compost. Water them daily, and sprinkle the top as well. Plant ASAP!

Pruning out the central leader during field production leads to a low-branched tree, which makes it easier for the homeowner to control the size and pick the fruit.

How do I plant this thing?!

Dig a hole wide and deep enough to accommodate the roots without bending them, typically 3' wide by 18" deep. The graft union should be out of the ground a couple of inches. You can add fertilizer to the backfill, but don't add compost.
Backfill, firm the soil, then soak the tree thoroughly. Tug it up a little if it settles. You don't want the graft buried, and you don't want the tree in a low spot. It should be "crowned up" an inch or so.
Make a basin for watering by pulling excess soil to form a ring around the tree. Water thoroughly again.
When it is dry, paint the trunk with an interior white latex paint, up to the first branches to prevent sunburn on the bark.

My watering advice for this area: give the tree one gallon of water every day until it leafs out and starts to grow. You don't need to water on rainy or foggy days. Then gradually water less often and more deeply. By May - June you should be able to have it on your regular watering cycle. The crucial watering time is March to early April, when we first get dry and warm. Don't let those fine root hairs dry out! A north wind in March kills lots of young bareroot trees.

What to choose?

The bins of bareroot trees can be a little overwhelming. There may be a dozen or more types of peaches, for example. Scores of roses. Lilacs, wisteria, flowering cherries, flowering plums, crabapples; shade trees. Nearby you may find artichokes, asparagus, rhubarb, strawberries, and even horseradish.

What's easy to grow?

Pomegranates, persimmons, and figs. Just plant, water, and wait. No pruning needed. All are tolerant of drought, but are not particularly susceptible to rot so they can be in a garden or even in or near a lawn. Cherries are very easy except for sensitivity to rot. No pruning or spraying needed.
But don't shy away from the other fruit varieties. Home orchard care is not difficult: some seasonal pruning and possibly some spraying. Organic options are available for the occasional pest problems. We are fortunate to live in an area where you can grow all the major types of stone fruits (apricots, peaches and nectarines, plums, pluots), the pome fruits (apples et al.), Mediterranean and Asian fruits, and more.
Factors in selecting a variety include flavor and ripening period, ease of size control, pest problems, chilling hours, and cross-pollination requirements, if any.

What about citrus?

Citrus trees may be available now, but not bare root as they are evergreen. It is an ok time to plant them, but warmer weather is optimal. Look for best selection of citrus in spring and summer. For more information: Dave Wilson Nursery L. E. Cooke Co. For a ripening chart, showing how to get fruit from your back yard year round: click here

Jargon: what's all this stuff on the label?

Semi-dwarf

I am getting away from this term as it is misleading. Some rootstocks make a tree grow more slowly. But they don't (usually) keep the tree much smaller than a regular rootstock. You determine the size of the tree by how you train and prune it. Exceptions: there are some extremely dwarfing rootstocks for apples that keep the plant miniature, small enough to grow in a tub or barrel. "Genetic dwarf" (miniature) varieties are available for peaches and nectarines, and there is a dwarf almond.

Rootstock

There are specific rootstocks for certain situations: nematode-infested soils, poor drainage. Mostly these are for commercial plantings. You may want to ask locally if you have a need for special rootstocks. If you ask me, the answer will be 'no'. If drainage is an issue, elevate your planting. If you want a smaller tree, prune it.

Pollenizers and pollinators?

"Pollenizer required." A few fruit varieties are self-sterile, either completely (Bing cherry) or partially (many apples). So they require the presence, within bee-flying distance, of another type which blooms at the same time. Not another tree of the same variety, but another variety. It can be in your neighbor's yard, or even a couple of doors away.
Apricots, peaches, nectarines, etc., are mostly self-fruitful.
Plums and pluots are complicated, so check before you buy, but there are some self-fruitful plums.
Some pears and apples are partially self-fruitful, and others will produce fruit without a pollenizer in our area but require one elsewhere.
The bee is the pollinator.

Chilling hours?

Deciduous fruit trees need a certain number of hours between 32 - 45F to break dormancy and develop their flowers properly. Too low chilling, the flowers don't open right. Low-chill varieties planted in cold areas may break dormancy too early, and try to flower while frost could still occur and damage the blooms. For more information on chilling hours, check out the UC Cooperative Extension Fruit and Nut Research and Information Center Website: http://fruitsandnuts.ucdavis.edu

written for the Davis Enterprise January 29, 2009

Choosing a Fruit Tree

2010-01-13T22:15:00.000-08:00

Choosing a fruit tree

Luscious fruit from your backyard! Enjoy Nature's bounty! Incredible tree produces four kinds of fruit! Live longer! Highest antioxidant fruit!

Selling the virtues of back yard fruit production is nothing new. "Step outside and pick an orange right off your own tree!" Citrus Heights, Orange County, Orangevale--these California place names reflect the sales techniques of early housing developers beckoning snow-bound easterners to California. A customer who moved here from Syracuse, New York, to retire had only two landscape requirements: an orange tree, and a palm tree. Such is the lure of California.

California's development history is intertwined with fruit trees. Since the Spanish padres brought seeds of the Spanish sweet orange (a seeded juice orange with thin skin, similar to our modern Valencia) and a thick-skinned lemon-like fruit, the earliest settlements by Europeans have taken advantage of the ideal fruit-growing regions of the state. The first citrus farm was planted in 1841 in Los Angeles, and William Wolfskill's oranges were selling in San Francisco during the Gold Rush for a dollar apiece.

Northern California growers quickly discovered that our climate was ideal for commercial production of stone fruits (apricots, cherries, plums, peaches and nectarines), and that these could be shipped back east for high profits because of the early harvest season here. All of these are readily grown as backyard trees. Apples are generally grown where autumn nights are cooler, and pears thrive in the Delta. In recent years Mediterranean and Asian fruits have become increasingly popular, and for good reason: persimmons, figs, and pomegranates are probably the easiest, lowest-maintenance backyard fruit trees.

So how do you choose a fruit tree? It's a very individual decision. The desirability of some fruits may outweigh the maintenance issues of the trees. Here's a checklist of considerations.

What do you have room for?

Ignore old-fashioned spacing and pruning recommendations designed for orchard production. Your goals are smaller trees, better quality fruit, and a longer harvest season, and YOU are in control of the size and production of the trees. You can plant trees very close together, prune each one severely to reduce the size of the tree and the quantity of the fruit, and choose varieties that ripen over a long period. With the right combination of stone fruits, Mediterranean fruits, and citrus, you could get fruit from your backyard every month of the year!

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What do you like? What would you actually use?

With more unusual fruits -- Asian pears, Fuyu persimmons, blood oranges -- you might want to try some from the farmer's market first. Though these keep much better than stone fruits, you may find your family just doesn't use that many--and by 'that many' I mean dozens or even hundreds.

What ripening period is important to you?

Consider a mix of 'styles' and fruit types so you have something different each period during the season. An excellent combination, if you have room, is

a self-fruitful cherry (May),
an apricot and an early peach (June),
a mid-season white nectarine (July),
a late-season pluot (with a pollenizer) and/or a late peach (August),
an Asian pear (September),
a pomegranate (October),
and a persimmon.
That would give fruit from late May through November! Citrus trees would round out the year, fruiting through the winter.
How patient are you?
If you're planting a fruit tree for your kids, you might want some fruit before they leave home! Peaches, nectarines, and plums all fruit on year-old wood, so you will actually get some fruit in the second growing season (thin off most of it so the tree can put its energy into growth). Spur-fruiting types such as apples, pears, apricots, and cherries take 3 - 4 years to produce fruiting wood.

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What is easy to grow?
This includes how much pruning or spraying will be needed, which have special pest or disease considerations, and which fruit blemishes or damages easily (making them more vulnerable to extreme weather and pests).
Apples and pears, for example, are really kind of a hassle here. The fruit is sure to get codling moth, the 'worm' in your apple, and managing that pest requires a combination of trapping, spraying, and picking up the spoiled fruit on the ground. (For more information, see our 'Pest Notes' at www.redwoodbarn.com).
Larger-fruited stone fruits are considered the most desirable fruits. The flavor of a summer peach just off the tree is incomparable! But these must be pruned heavily or the branches will collapse from the weight of the fruit. This especially includes peaches, nectarines, plums, and pluots. It's important to keep a dense canopy so that the fruit isn't damaged in 100+ degree weather. Peaches and nectarines also require spraying to prevent peach leaf curl. These winter chores aren't very difficult, but must be done each year, and summer pruning techniques can be used to manage the tree size.
Persimmons, pomegranates, figs, and citrus, on the other hand, require no pruning or spraying at all. They can be pruned for size control, but it isn't necessary.
Which trees look nice in the landscape?
This can be an important consideration, as your fruit trees can be part of your landscape. Some have very showy flowers: 'Red Baron' and 'Fantastic Elberta' peaches, 'Garden Prince' almond (also a naturally small tree), and others. Cherries are a mass of white blossoms in early spring, with a narrow upright habit suitable to side yards or corners.
Some have all-season beauty: persimmons have vivid chartreuse new growth in spring, attractive shiny leaves in summer, golden fall color, and the winter fruit is showy even if you don't eat it (don't worry, the birds will!). Apricots and pie cherries have graceful spreading growth habits. And citrus trees have fragrant spring flowers, nice evergreen foliage, and colorful fruit all winter.
You really can 'enjoy nature's bounty!' and 'have luscious fruit from your back yard!' A little planning can just make it easier and more satisfying.

Written for the Davis Enterprise, January 27, 2005

Rose Pruning is Easy!

2010-01-02T11:09:00.000-08:00

Rose Pruning is easy!

Why do we make kids do word problems in math? Or those odd reading comprehension exercises? One of the important lessons is weeding out extraneous information to get to the point (some people never learn this).

I’ve always liked the "…. For Dummies" book series, because there is a tacit acknowledgment that the reader, while interested in the subject, has no background knowledge and doesn’t already speak the jargon. Much gardening advice comes cluttered with big words and assumptions about your knowledge, often cloaked in the odd 19^th century writing style garden writers adopt. "These floriferous specimens are not unworthy of consideration by the discerning plant enthusiast…." (Read: they flower a lot; you might like these!).

Roses, being the most popular garden flowers by far, have more than their share of this, so there is a perception that pruning is complicated. Bosh! Rose pruning is simple. And here’s an important point: rose plants are very forgiving. If you prune them ‘wrong’ you might get fewer blossoms (at first), but you won’t kill the plant.

Here’s a summary. The jargon is highlighted for further explanation.

• When: prune when dormant between mid-Dec. and early Feb.

• Tools: Hand pruners, loppers, narrow saw, coated gloves.

How:

• Remove dead stuff.

• Cut off suckers.

• Open the center.

• Remove all except 4 - 6 canes.

• Cut these back about by half, more or less.

• Cut to a bud pointing outside, about 1/4" above the bud.

• Remove and rake up remaining leaves.

• Apply dormant spray. (optional)

• Dab light colored sealer (Elmer's Glue!) on end of each cane. (optional)

That’s it!

Dormant means the rose is not actively growing. Roses don’t get the message here to drop their leaves, and they continue putting out buds and flowers into December. New buds start to push and grow in February, but that isn’t too late. It just gets harder to see what you’re doing, and delays the first bloom.

My pruning tools are a good, newly sharpened pair of bypass pruners (the kind that cut like scissors–I prefer Felco brand) and a narrow folding pruning saw. A keyhole saw also works. The idea is that the bushes can be dense and hard to get into, so a narrow blade is helpful. Loppers are long-handled pruners. I use them first, just to ‘lop’ off the top growth and get it out of the way. Gloves that are coated with nitrile resist thorns. Some gardeners use a reciprocating saw (SawzAll) for removing old, dead wood–rose wood is surprisingly hard.

Suckers are vigorous shoots that sprout from below the graft. These are a different kind of rose and will overgrow the desirable top part of the plant. If they are coming from below ground, dig the soil away a bit so you can cut them off from the root or stem. Sometimes I get fed up with a plant that is constantly suckering and give it one good pruning: with a shovel.

To open the center we take out crossing branches, twiggy stuff– anything cluttering the inside of the bush. The purpose is to allow more light and air into the bush, reducing diseases.

Canes are the strong stems or branches on which the most common roses (Hybrid Teas and Grandifloras, specifically) flower. New canes are red, old canes are grey. Old wood is more prone to borers and diseases, so we want to remove old ones and leave new ones. A healthy rose is putting out a few new canes each year, so we are choosing the biggest ones and removing the rest. The best ones to leave are those which encourage that open form.

Some types of roses don’t have obvious canes. Don’t worry about it; just thin out the twiggy stuff and cut the plant back about 50%. Landscape and shrub roses don’t even have to be pruned except to remove dead wood.

How far you cut these back will determine the size and abundance of your spring bloom. Cut ‘em to 18" from the ground and you’ll get fewer blooms, but they’ll be bigger and have longer stems. Leave ‘em 30" or more and you’ll have more blooms on shorter stems. The plant doesn’t care either way!

Rather than worry about how far back I’m cutting, I usually cut to a bud (the swelling thing that’s starting to grow, found at the base of a leaf or where one was) which is well positioned (more of that 19^th century prose…). The bud will grow in the direction that it is pointed. To enhance that open growth habit (again, to reduce leaf diseases), look for one pointing outwards. On the other hand, if your roses are along a walk cut to one that is pointing to the side or away from the path!

There are four fungus diseases that attack rose foliage, and they overwinter on the leaves. Reducing those diseases is one of the primary goals of pruning. Pick off all the remaining leaves if you have the patience and rake up the ones on the ground. That cleanup helps a great deal in reducing reinfection in the spring. Spraying the bushes with a fungicide containing copper or sulfur creates a barrier on the stems and new growth which blocks the reinfecting spores. Helpful, but not essential.

I never used to recommend sealing the ends of the cut canes. The old black pruning sealants are harmful, absorbing heat (because of their color) and trapping moisture. But sometimes you find hollow canes that appear to have died back. These are inhabited by cane-nesting wasps or carpenter bees. The damage they do is slight, but the moisture trapped in the cane can lead to dieback. So daubing on some light-colored sealant can block their entry. Elmer’s glue just happens to come in a handy applicator, and does the job nicely.

Pruning of climbing roses which bloom all spring and summer follows the same general principles: cut out dead stuff, remove the oldest canes if you can, and shorten the plant. We just cut them back roughly to the support on which they are growing.

A few types of climbers (and some old-fashioned roses) bloom only on last year’s growth (‘old wood’). So when you prune these in the winter, you're removing next spring's flowers! It won’t hurt them, but it kind of defeats the purpose for which you’re growing them! Wait until after that bloom is done, and then cut these back as severely as you wish in the late spring. Rose experts can help you figure out what kind you have from a description, a blossom, or a picture.

One to two cups of Alfalfa meal and a couple of tablespoons of epsom salts are often applied as a last step. The alfalfa meal contains a small amount of nitrogen, as well as plant hormones which stimulate the growth of new canes. Epsom salts, obtainable at pharmacies or garden shops, are just magnesium sulfate. The magnesium helps make the leaves greener and healthier, and the sulfate reduces the soil pH–both helpful in our area.

Don’t be scared–pruning is simple in concept. As with children, we are correcting faults and encouraging them with a little loving discipline. They have thorns, and you have pruners, so this is one case where you CAN say "this is going to hurt me more than it’s going to hurt you!"

Written for the Davis Enterprise, January 22, 2004

Dormant Pruning: Keep It Simple.

2010-01-02T10:59:00.000-08:00

Dormant Pruning: Keep It Simple.

"The best time to prune fruit trees is when you have enough time to finish the job, anywhere between November through March." —Oregon State University

I have written about dormant pruning before. Lots of descriptions, principles, background information. But every now and then I get someone who wants it plain and simple. No embellishments. How-to-prune in 1000 words or less. Short declarative sentences. Ok.

These recommendations are for deciduous fruit trees (and vines). Citrus are evergreen subtropicals, best pruned when there is no risk of frost damage.

Basic principles:

Proper pruning enhances trees; improper pruning endangers them.
Remember the goals (different than for shade trees!): control the structure and size of the tree, control the amount of fruit.
Look at where the tree produces fruit: all along the branches on last summer's wood, or on short 'spurs' on older wood.
Most pruning is a combination of thinning some branches, shortening others.

Why prune fruit trees?
To improve the structure of the tree, to control the size of the tree for easier harvest, and to reduce fruit production of larger-fruited types.

When? Winter (between December and the end of February is best).

Remove diseased, dead, crossing or rubbing branches.
Reduce the height of the tree.
Remove lots of fruiting wood on heavy-bearing trees.
Train young trees: select what will be the permanent branches, and prune out the center of the tree if you want a more open habit.
Summer (after mid-July):
Control size by cutting back new growth -- like a hedge if you like -- to keep the tree within picking height.

How do I prune specific types of fruit trees?
Keep in mind the principles: better structure, smaller size, control fruit. Know where each type produces fruit.
Regardless of the type, always begin by removing dead, diseased, crossing, rubbing branches, and strongly upright shoots (suckers).

Severe pruning required every year:

Peaches, nectarines.

Hint: Look for the red branches with fuzzy buds. That's where the fruit will be.

Fruit is produced all along last summer's growth (see illustration below). On peaches and nectarines, last year's growth is conveniently red, older wood is grey. Thin out about 50% of what grew last year, and shorten the remainder by 50%. Yes, reduce fruiting wood by 75% -- or more!

Plums, pluots.

Produce on spurs AND along last summer's growth. May seriously overproduce. Thin out the many suckers these produce (strong upright shoots), cut back last summer's growth at least 50%. You'll get lots of fruit no matter what you do.

Moderate pruning required most years:

Apricots, apples, pears, and Asian pears.

Prune to make the trees shorter.
Cut out strongly upright branches, thin these trees by about 25%.
Fruit is on short spurs which grow on 3 - 4 year old branches.
Apricot spurs (below) produce for a few years, the others fruit for many years. Older trees may produce far more fruit than you want. It's ok to thin more heavily as the trees get older.

Light or no pruning required:

Sweet cherries.

Prune to shorten if you want, but they can be beautiful large trees if you prefer (the birds will thank you). Fruit on spurs which produce for many years. Don't prune severely. Pie (sour) cherries have a graceful, spreading habit and only need light thinning.

Persimmons and figs.

Persimmons: no pruning required except to thin crossing branches. Strong wood can hold large crops, and they are very ornamental trees. Sometimes pruned for size control.
Figs: prune severely for size control (you'll still get plenty of fruit), or allow them to become big tropical-looking trees -- and get even more fruit. Your choice.

Pomegranates, jujubes, and quince.

Large shrubs don't need to be pruned at all. Can be trained into small, multi-trunk trees (keep removing suckers), or sheared as a hedge, or topped for size control. You'll still get more fruit than you can use!

Nut trees.

Thin lightly and allow them to grow as big as they want, since we harvest off the ground. Pecans need careful training for safe branch structure, and, like walnuts, are very big trees. Neither takes well to size control. Almonds are good small back yard trees: thin lightly if at all.

Other fruit plants.

Grape vines.

Fruit on one-year old branches.
Thin out most (75% or more) of the long branches that grew last summer.
Shorten the other branches to about 3 4 buds -- unless you have Thompson Seedless. For that variety, count out and cut to about 8 buds or more. If you don't know what you have, prune like Thompson Seedless.
Generally 30-50 buds are left per mature vine regardless of the pruning system.
http://homeorchard.ucdavis.edu/Grapes.html

Kiwi vines.

Fruit on one-year old branches, like grapes.
Cut out more than half of last year's growth and shorten up the rest to 3 4 buds. Prune vigorous, tangled growth in summer if necessary.
http://www.homeorchardsociety.org/article/22/

Berries.

Caneberries: blackberries, Boysen, Olallie, Marion, Logan, etc.
What grew last summer fruits this spring, and never fruits again. Remove branches that have fruited, leaving the new ones. It's easier to tell them apart in the summer or fall, but the pruning can be done anytime. Winter is a handy time to tie up the sprawling vines.

Raspberries.
Published information is very confusing. Some produce in spring, some in summer, some both. Most don't produce well enough here to bother, frankly, but in general they are thinned to remove weak canes in the spring, sometimes are headed at that time, and then canes which have fruited are removed when they're done (usually in late summer).

Blueberries.
Fruit is produced on year-old wood on attractive shrubs. Pruning is similar to roses. Thin out old shoots from the base, leaving 4 6 of the newest ones. Shorten some of the remaining branches by a foot or so.

Written for the Davis Enterprise, Jan. 26, 2006

Redwood Barn Nursery

Fruit trees are in!

After The Frost: What To Do?

Some common questions:

On a more cheerful note, how about some color in the garden in mid-winter?

Tree Associates Blog

Do you have an Android?

Frost warning? Freeze Warning?

What weather conditions lead to a frost warning?

What would prevent the frost?

What's the potential for harm in the garden?

A frost is not a freeze.

Which plants are we going to lose on a frosty night?

Which plants should we protect from frost?

Which plants should we protect from a freeze?

There are two main ways to protect plants:

Trap heat.

Provide heat.

Poems:

Choosing shrubs to use less water

What about your existing shrubs?

Careful plant selection is another approach to reducing your water bill.

Some plants usually grown as trees can be grown and pruned as shrubs.

Easy Steps to Water Conservation

Easy Water Conservation.

First is to water correctly.

Second is to zone your plants by water need.

Third is to reduce lawn area if possible.

Fourth is to choose plants that use less water.

Herbaceous (soft) ground covers

Vines that are planted as ground covers.

Shrubby ground covers

How to do it.

Bulbs!

From the Davis Enterprise, October 28, 2004Click here for a newer article.

Some technical terms.

How do you plant them?

Daffodils and narcissus

Some good daffodil choices:

Good narcissus choices:

Irises

Tulips, hyacinths, and crocus

'Minor' bulbs.

Good 'minor' bulbs for this area:

A Zen Garden In Davis

What was your motivation or inspiration for planting a zen garden?

Did it replace an existing landscape?

What year was the project begun, and when was it completed?

Who helped with your design and installation?

Tell us about selecting and installing the rocks.

Where did you buy your bamboo? Why did you select that species (Temple bamboo, Semiarundinaria fastuosa)?

Just to verify: your barrier is a concrete trench 4 feet deep, six inches wide, with concrete rebar at 1 foot intervals. Watering is via drip soakers. How often do you run them? What other maintenance do you do?

Some further notes:

We get questions...

In the flower garden:

In the orchard:

In the landscape:

General and wacky:

A cautionary note:

Common Landscape Errors

or ... It Isn't The Plant's Fault!

Mulch too close to the tree.

Watering too often.

Staking too close, too tight, and too long.

Wrong pruning tools.

Topping trees.

Wrong plant, wrong place.

Misapplication of herbicides.

Continued use of plants with known pest problems.

If April showers bring May flowers, what do May showers bring?

Fungus!

Lavenders!

What's that purple flower?!?

What do lavenders want?

Which smell best?

Which look best?

When do they bloom?

A gallery of lavenders

Here is a summary of the types,

Easy Edibles!

From the Davis Enterprise, October 28, 2004

Click here for a newer article.