Saturday, September 24, 2011

A Zen Garden In Davis


Written for the Davis Enterprise, August 25, 2011

Click on any image for a larger version











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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.


Thursday, August 25, 2011

We get questions...

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

Saturday, July 16, 2011

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

Tuesday, June 21, 2011

Common Landscape Errors

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.

Sunday, May 29, 2011

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

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.

Wednesday, May 4, 2011

Lavenders!

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.

Wednesday, March 30, 2011

Easy Edibles!

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








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

www.redwoodbarn.com