Blueberries?

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?




An offhand question got me ruminating on plums. This started out metaphorical; ruminating as in thinking about or pondering. But ruminating also means chewing on, and Nugget Market had a beautiful display of plums. So I paid the flown-in-from-Chile price and ate some. Just to get the juices flowing. Metaphorically and literally, again.
Her question was "do you have any heirloom fruit trees? I've heard they're better than hybrids."

Now this dichotomy of heirloom vs. hybrid usually comes up during the spring vegetable season as the popularity of heirloom tomato varieties has increased in recent years. Advocates tout flavor, historical value, regional adaptability, genetic diversity, and more. Plus, you can (carefully) save the seed from your heirloom tomato and it will grow (mostly) the same variety next year. You can't do that with hybrids. Hybrid varieties generally have better disease resistance, greater vigor and productivity; many are more regionally adaptable, and many have outstanding flavor as well.

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

But does the term heirloom apply to fruit trees? And what does it mean, anyway? The folks at the Slow Food movement (www.slowfoodusa.org) have developed an Ark of Taste: lists of plant varieties that they believe should be grown, sought out, and appreciated, including what they call heirloom fruit varieties. Some they believe are on the brink of extinction, at risk of being displaced forever by newer commercial varieties. Others have just been around for a long time and have special merit for flavor and history.
A few examples suited to California: Sebastopol's Gravenstein apple, the Blenheim apricot, Meyer lemon, Mission olive, important peaches such as Fay Elberta, Rio Oso Gem, and Sun Crest, and plums including Elephant Heart, Laroda, and Mariposa (which was bred in Winters in 1943).
Since many of these are hybrids, clearly this definition of 'heirloom' is based on longevity. Meyer lemon was introduced from China in 1907 by USDA scientist Frank Meyer, and is probably a hybrid between a true lemon and a mandarin. Elberta peaches were from the prodigious breeding efforts of Luther Burbank, who also introduced many of the plums that we know today, as well as the blight-resistant Burbank potato, Shasta daisies, and many other garden treasures. Sometimes a variation occurs naturally, gets noticed by a grower, and is propagated clonally. More often, fruit tree varieties have been intentionally created in hybridization programs.



Roses

Rose growers use the term heirloom to refer to any rose variety that was in existence before 1867. That is the year that the first Hybrid Tea rose was introduced. This cross between Hybrid Perpetual roses and the sensational new Tea roses that had been brought to England from China revolutionized the rose industry, creating the class that has dominated the nursery and florist trade ever since. So all those old Hybrid Perpetuals, Bourbons, and other types that you would have found in any early 19th century garden? Those are the heirloom roses.



Vegetables

Vegetable growers tend to use stricter definitions of heirloom. Some say it only includes varieties introduced before 1951, when hybrid varieties from inbred lines were introduced. This seems a little arbitrary. Burpee Hybrid tomato was introduced by W. Atlee Burpee Co. in 1945. Hybrid corn was invented in 1879 and grain hybrids from inbred lines were introduced in the early 1900's. But it wasn't until the 1950's that hybrid varieties became common in the seed catalogues for home gardeners.
More commonly people use the term to apply to old "open-pollinated" varieties. Let's say you get seed of a good tomato from a friend. You like it because it grows big, produces lots of fruit, and the fruit is very tasty. Or unusually large, or a different color, or striped. So you save the seed of the best producing plants and you grow that the next year. Since tomatoes are self-pollinating, all you have to do is cover the flower to make sure no stray bee brings pollen from another type of tomato.
Each year you save seed only from the plants that have those desirable characteristics, and grow that seed the next year. You haven't crossed selected parents to create your seeds, as is done with hybrids. Your seedlings are not exactly the same, but they are close enough to be considered homozygous. Within a few generations the traits are stable and the variety is established. That's how old varieties such as Brandywine, Mortgage Lifter, Mr Stripey, etc., have been preserved and passed on for generations.

Sometimes people want to know if the seeds or seedlings are "genetically modified." While traditional hybridizing could be considered a form of genetic modification, usually the term refers to new plants created by gene splicing: inserting a gene, as with CalGene's FlavrSavr¨ tomato introduced in 1991. No seeds or seedlings available to home gardeners are created this way.



A labor of love?

Most people have no idea how long it takes to develop a new hybrid. George Ball Jr., owner of Burpee Seed Co. and Heronswood nursery, wrote in his blog Heronswood Voice:

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.
"A new pot cyclamen averages 10 years of constant attention, while the tuberous-rooted begonia takes about 12 years. On the more optimistic end, an experimental pansy breeder can introduce a new cultivar in about 3 to 4 years. Tomatoes average 4 to 5 years, bell peppers 5 to 6 years and cucumbers and squash 7 to 8 years. Our recent Heronswood Hellebores took 13 years-from the first selections in 1993 to the introductions in 2006. (Yet, consider how inexpensive flowers and vegetables are.)"


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.

Dr. Carl Whitcomb grew 26,000 Lagerstroemia seedlings before he found the wine red foliage he was looking for in the fourth generation. The fifth generation yielded mildew resistance and fragrance, and true red flowers emerged in seedlings of the sixth generation. Some crape myrtle seedlings will flower in the first year, but most take 2 - 6 years. After seven years he had narrowed the seedlings down to a few, including the bright red Dynamite¨ that has become so popular. By 1999, 14 years after embarking on his quest for mildew-resistant crape myrtles with vivid colors, Dr. Whitcomb had grown over 160,000 seedlings. His patent on Dynamite¨ and several other varieties provides some income, but clearly this is a labor of love.

Breeders take a variety of steps to speed up the process.
One of my first jobs as a teenager was tying up cantaloupes. The breeder was growing them in a greenhouse for faster growth, hand-pollinating them, and my job was to fashion slings from his wife's old pantyhose to suspend the fruit from trellises in order to save space. Cantaloupe vines are itchy and greenhouses are hot. I don't recommend this job.
A fruit tree seedling may take 3 - 5 years to produce fruit, but if the seedling wood is budded or grafted onto a mature tree it will fruit sooner.
Breeders of annual flowers and vegetables maintain growing facilities in the northern and southern hemispheres to double their growing seasons. "They 'grow out' selections every six instead of twelve months-and spend a lot of time flying back and forth to Peru, Chile, South Africa, Southeast Asia, Australia and New Zealand," says Ball.

So in the world of fruit trees, an heirloom variety is simply one that has stood the test of time. I don't recommend getting too dogmatic when it comes to tomatoes. I always suggest planting some hybrids such as Early Girl and Celebrity for reliable production and flavor, and some heirlooms for variety. Most of the heirloom tomatoes are regionally adapted to the east coast or Midwest: Brandywine, the famous Amish heirloom, barely produces in the Sacramento Valley heat (my plant produced four fruit last year). California gardeners need to start developing our own seed strains. Then if we wait fifty years or so, we can call them heirlooms.

Written for the Davis Enterprise, February 26, 2009

Starting summer vegetables from seed!

Garden centers will have lots of seedlings of tomatoes, peppers, and eggplant at the proper planting time. But there may be unusual varieties you wish to grow. Starting seeds indoors can be a fun project. You may wish to save a little money, or make sure that your seedlings are organically grown.
But the indoor environment is not ideal for vegetable plants.
o Low light and lack of air movement cause plants to "stretch" and become leggy. There is the risk of attack by seedling diseases.
o If you start your seeds too far ahead of outdoor-planting weather, they become very tall and undergo transplant shock when you finally move them out.

Given these limitations, the following guidelines will help you succeed:

When to plant

o Start tomato seeds 6 to 8 weeks ahead of your outdoor planting time. We plant outside in late April or May here. Tomato seedlings sprout in about a week and grow very quickly.
o Start pepper and eggplant seeds 10 to 12 weeks ahead of your outdoor planting time. We plant them outside in May here. These seeds sprout in 1 to 2 weeks and grow rather slowly.

Planting by the calendar? Tomatoes grow faster, but can be planted out earlier. Peppers and eggplant grow slower, and require warmer soil outdoors. So February is the ideal month to start all of them here. Just be aware that you will hold your pepper and eggplant seedlings a few weeks longer than your tomatoes before putting them in the ground. March is ok; April is too late from seed.

Read the whole article here

It's bareroot season!

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

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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

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?

This is less important than you might think, based on newer spacing and training techniques. Many methods have been promoted over the years to enable home gardeners to get fruit production in small yards. Miniature trees, multiple grafts, dwarfing rootstocks, close spacing, espaliered trees, and summer pruning all enable you to get more trees in your yard, and more fruit per square foot. Of these techniques, the close spacing and summer pruning are the easiest ways to get high yield from outstanding varieties.

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?

A fully-grown tree trained in the traditional 'orchard' style can produce hundreds of fruit! Soft-fruited types don't store well, and that is a LOT of fruit to eat or process in a few days.or pick up off the ground. It can be a considerable mess. Reducing total fruit production may be a major goal of pruning peaches, nectarines, plums, pluots, and (to a lesser degree) apricots and figs. These are all ripe for only a few days. So training them as small trees or shrubs, and pruning severely, enables you to plant several varieties and extend your harvest. On the other hand, cherries are so popular with birds that you don't have to worry about the fruit being a mess.

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?

My own experience is that earlier-producing varieties of any particular fruit get heavier use in our household. The peach that ripens in June is prized; by late July you've eaten a lot of peaches. Early varieties are also less damaged by extreme heat. But the 'all-purpose' varieties tend to be mid- to late-season, and may have higher sugar content. Consider firmer textured varieties for mid and late season, as they will be more useful for pies, freezing, and canning. Or buy a good fruit dryer--nearly all fruit can be dried, including some that would surprise you (dried Asian pear slices are like candy).

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!

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.

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