Wednesday, November 28, 2012

Persimmon: THE Edible Ornamental of Autumn

California's Central Valley is ablaze with the other orange fruit tree currently: the brightly colored persimmon. And it's not just the fruit.

Persimmon tree leaves can turn a brilliant hue of red before the first big wind and rain storm of late November washes them off their branches. 

What's left behind is the unpicked fruit, dangling like holiday ornaments during December. That's a feast for our well as a banquet for hungry birds.

Persimmons have adapted well to our California climate: warm, dry summers and mild winters. At least 500 different Japanese persimmon (Diospyros kaki) varieties were brought to California during a major planting spree from 1870 to 1920. In 1877 alone, more than 5,000 plants in 19 varieties were imported from Japan. As a result, 99% of the commercial persimmon crop is grown here in California.

Persimmons are quite nutritious, as well, loaded with Vitamin A, Vitamin C, Fiber, and antioxidants such as Beta-Carotene and Lycopene. 

If you live in the Central Valley, Southern California, Bay Area or low foothills ... you can grow that! Bare root persimmon trees will be available at local nurseries during late December, January and February. 

360-degree mini-sprinkler from Dripworks

Give them full sun and a regular irrigation in the dry months for best production. Persimmon trees can tolerate partial shade.

Persimmons are usually classified as either astringent or non-astringent. For fresh eating straight from the tree, choose a non-astringent, self-pollinating variety such as Fuyu, Giant Fuyu, Yemon or Izu. Astrigent varieties, which need to soften thoroughly before they sweeten, include Hachiya, Chocolate or Tamopan. Those varieties are self-fruitful, as well.
A partial harvest from one, 7-foot tall Yemon persimmon tree

Persimmon growing advice from the California Rare Fruit Growers (CRFG):

Location: Full sun with some air movement is recommended for persimmon trees in inland areas, although they will tolerate some partial shade. Persimmons grown in cooler areas should have full sun with protection from cooling breezes. As an attractive ornamental the tree fits well in the landscape. It does not compete well with eucalyptus.

Soil: Persimmons can withstand a wide rage of conditions as long as the soil is not overly salty, but does best in deep, well drained loam. A pH range of 6.5 to 7.5 is preferred. The tree has a strong tap root which may mean digging a deeper hole than usual when planting (when on D. kaki stock).

Irrigation: Persimmon trees will withstand short periods of drought, but the fruit will be larger and of higher quality with regular watering. Extreme drought will cause the leaves and fruit to drop prematurely. Any fruit left on the tree will probably sunburn. Some 36 to 48 inches of water are needed annually, applied gradually in spring and tapering off in the fall. Hot inland areas may require 2 or 3 applications weekly, while coastal areas may need watering only once every 6 weeks, depending on the soil. If a drip system is is used, the emitters should be moved away from the trunk as the tree matures.

Most trees do well with a minimum of fertilizing. Excess nitrogen can cause fruit drop. If mature leaves are not deep green and shoot growth is less than a foot per year, apply a balanced fertilizer such as a 10-10-10 at a rate of 1 pound per inch of trunk diameter at ground level. Spread the fertilizer evenly under the canopy in late winter or early spring.

Pruning: Prune persimmon trees to develop a strong framework of main branches while the tree is young. Otherwise the fruit, which is borne at the tips of the branches, may be too heavy and cause breakage. A regular program of removal of some new growth and heading others each year will improve structure and reduce alternate bearing. An open vase system is probably best. Even though the trees grow well on their own, persimmons can be pruned heavily as a hedge, as a screen, or to control size. They even make a nice espalier. Cut young trees back to 1/2 high (or about 3 feet) at the time of planting.

Pests and Diseases: Persimmons are relatively problem-free, although mealybug and scale in association with ants can sometimes cause problems. Ant control will usually take care of these pests. Other occasional pests include white flies, thrips which can cause skin blemishes and a mite that is blamed for the "brown lace collar" near the calyx. Waterlogging can also cause root rot. Vertebrate pests such as squirrels, deer, coyotes, rats, opossums and birds are fond of the fruit and gophers will attack the roots. Other problems include blossom and young fruit shedding, especially on young trees. This is not usually a serious problem, but if the drop is excessive, it may be useful to try girdling a few branches. Over watering or over fertilization may also be responsible. Large quantities of small fruit on an otherwise healthy tree can be remedied by removing all but one or two fruit per twig in May or June.

Harvest: Harvest astringent varieties when they are hard but fully colored. They will soften on the tree and improve in quality, but you will probably lose many fruit to the birds. Astringent persimmons will ripen off the tree if stored at room temperature. Nonastringent persimmons are ready to harvest when they are fully colored, but for best flavor, allow them to soften slightly after harvest. Both kinds of persimmons should be cut from the tree with hand-held pruning shears, leaving the calyx intact Unless the fruit is to be used for drying whole, the stems should be cut as close to the fruit as possible. Even though the fruit is relatively hard when harvested, it will bruise easily, so handle with care.

Storage: Mature, hard astringent persimmons can be stored in the refrigerator for at least a month. They can also be frozen for 6 to 8 months. Nonastringent persimmons can be stored for a short period at room temperature. They will soften if kept with other fruit in the refrigerator. Persimmons also make an excellent dried fruit. They can either be peeled and dried whole or cut into slices (peeled or unpeeled) and dried that way. When firm astringent persimmons are peeled and dried whole they lose all their astringency and develop a sweet, datelike consistency. 

Yemon Persimmon

And we are in total agreement with the CRFG: persimmons make an excellent dried fruit, a great sweet snack or for use in cookies or breads!

According to our favorite book on dehydration techniques, "How to Dry Foods" by Deanna DeLong:

• Wash and remove the stem cap. Cut fruit in half and then into 3/8-1/2" slices.
• Place on a dehydrator sheet in single layers.
• Dry at 140 degrees for 1-2 hours, then reduce heat to 135 degrees for an additional 7 hours (approximate).
• When done, they should be tender and pliable, but not sticky.

At that point, you can either vacuum seal them in plastic bags for long term preservation, or store the dried persimmons in a canning jar for quick use.

Backyard gardeners who do a lot of drying are passionate about their choice of dehydrators. Some prefer the rectangular Excalibur dehydrator ; others (including our household) enjoy the circular Nesco American Harvest Dehydrator . Our largest complaint about the Excalibur: the fan blows from the back to the front, which can rearrange any lightweight herb leaves that you might be trying to dry. The Nesco American Harvest dehydrator's fan moves warm air from the bottom up, offering less disturbance to the drying crops. Still, the Excalibur is a good choice for most fruit and vegetable drying.

Monday, November 19, 2012

Innovative Controls for Peach Leaf Curl

It's November. Another cool, wet autumn has arrived in Northern California... 

...And with it, the eventual return of peach leaf curl in 2013.

 Peach leaf curl causes leaves of peaches and nectarines to discolor, thicken, pucker, curl, distort and eventually fall off. The fungus overwinters in these trees as spores, usually in the new buds. The rains of late winter and early spring 2012 splashed these spores onto the emerging leaves, causing more problems. Emerging shoots can die; fruit production can be reduced in severe infestations. Only rarely do reddish, wrinkled areas develop on fruit surfaces; later in the season these infected areas become corky and tend to crack.
         The good news is that a second set of leaves soon emerges and can develop normally when the rains cease and daytime temperatures steadily reach into the 80's. The bad news: too many years in a row (perhaps 3) of a serious peach leaf curl infestation can kill peach and nectarine trees.


 Studies at UC Davis have shown that nipping off infected leaves of peach and nectarine trees doesn't do much good.

The best thing you can do this fall and winter is to assist those trees through this stressful period. 

• Rake up any fallen leaves and pull weeds that are growing beneath the drip line of the trees.

• After cleanup, spread four inches of fresh organic mulch beneath those fruit trees. Organic mulches, such as compost, shredded branches or the fallen leaves of healthy shrubs and trees will help conserve soil moisture, hold down weeds and add nutrients to the soil as that mulch breaks down.

• Pruning in fall prior to applying any fungicides can reduce spore numbers overwintering on the tree and reduce the amount of fungicide needed. 

• If leaf curl symptoms occurred on your trees last spring, be sure to treat them now to prevent more serious losses the following year.
         The experts at UC Davis advise pruning infected peach trees in the fall before spraying with a copper ammonium complex product with 1% horticultural spray oil added to the mix.

    In the good old days of fruit tree sprays (2009), 50% copper concentrates were the recommended course of action. Not any more. Copper sprays, such as Liquicop available currently are weaker (about 8% concentration). Lime sulfur has been removed from the market. Bordeaux mixtures are expensive and wasteful...and potentially caustic.

And to add insult to injury: tests conducted at the Fair Oaks Horticulture Center by Chuck Ingels, UC Farm Advisor, show that the older, stronger copper sprays that are no longer available (Microcop, for example), along with lime sulfur, did provide the best control.

The trial earlier this year involved treating (or not treating) individual branches on 10 different peach and nectarine trees

Still, that study did provide some good news about the future of peach leaf curl control:

The future of peach leaf curl control?
"Compared to untreated branches, Liquicop-treated branches averaged about 70% control," says Ingels. "Copper soap was slightly better at 80% control, Agribon (row cover material)  by itself was less effective at just under 60% control, and both Agribon + Liquicop and lime sulfur (late fall) followed by Microcop (late winter) resulted in nearly complete control.  Maxicrop (sea kelp) did not work at all and seemed to increase the severity on some of the branches."

The UC Davis Integrated Pest Management information on controlling peach leaf curl says, "Fixed copper products include tribasic or basic copper sulfate, cupric hydroxide, and copper oxychloride sulfate (C-O-C-S), but currently only liquid products containing copper ammonium complex products with 8% MCE (e.g., Kop R Spray Concentrate [Lilly Miller brands] and Liqui-Cop [Monterey Lawn and Garden]) are available to consumers. The most effective copper product, 90% tribasic copper sulfate with a 50% MCE (Microcop) is no longer available to retail outlets, because the manufacturer withdrew the product in 2010, although remaining supplies still can be sold."  

One of the reasons for that removal: repeated annual use of copper products over many seasons can result in a buildup of copper in the soil, which eventually can become toxic to soil organisms, and if it moves into waterways, can harm some aquatic species.

The removal of lime sulfur products was prompted by a rash of self-inflicted deaths in Japan in 2008 called "Detergent Suicides", which has since spread to the United States.

Bordeaux mixtures, a combination of copper sulfate, hydrated lime and water, are effective in controlling peach leaf curl, but come with their own set of warnings. According to the UC IPM Guideline entitled "Bordeaux Mixture":  "When applying Bordeaux, be sure to wear protective clothing, including goggles, because the spray deposit is corrosive, can permanently stain clothing, and is difficult to wash off." They also recommend wearing a dust and mist-filtering respirator when mixing in the hydrated lime. And that mixture can discolor anything it touches, including buildings and fences.

Although you can purchase pre-packaged Bordeaux Mixtures, they are not as effective as the mixture made from the individual components, reports that UC IPM Guideline. And that brings up the cost and waste involved: copper sulfate and hydrated lime are usually sold in large quantities, much more than the average homeowner needs for the backyard peach and nectarine trees. Storage involves mixing the leftover individual ingredients separately in water and storing in their own sealed jars. That UC IPM Bordeaux Mixture Guideline warns: "Be sure to clearly label both stock solutions and store them where children can’t get into them, since these materials, especially the copper sulfate, are very toxic and corrosive."

The synthetic fungicide chlorothalonil is the only non-copper fungicide available for managing peach leaf curl in the backyard orchard. Although one fall application may help prevent a spring outbreak of peach leaf curl, a second application in January or February, as the buds begin to swell, can be beneficial, as well.

But be sure to read and follow all label directions if you choose to use chlorothalonil, including this
"This product is toxic to aquatic invertebrates and wildlife. Do not apply directly to water or to areas where surface water is present or to intertidal areas below the mean high water mark. Drift and runoff from treated areas may be hazardous to aquatic organisms in neighboring areas."

Or this:  "May be fatal if inhaled. Harmful if swallowed or absorbed through skin. Causes moderate eye irritation. Avoid contact with eyes, skin or clothing. Do not breathe spray mist.

Or this: "This product contains chlorothalonil which is a
chemical known to the State of California to cause cancer."

No matter which spray method you choose, several days of dry weather must follow for the products to work. And that was the frustrating part of the winter of 2011-2012: the weather was comparatively dry during December, January and February...perfect for spray applications. The wet March and April provided the perfect vector for peach leaf curl, splashing spores of the disease to those branches that were unsprayed or incompletely sprayed.
         There are peach varieties that are more resistant to peach leaf curl. The downside: they may not be as flavorful as you might like. Peach varieties reported to be more leaf curl resistant include Frost, Indian Free, Q-1-8 and Muir; among nectarines, only the Kreibich variety is resistant, says UC Davis.

And for those who want to provide a helping hand next fall and winter to their suffering peach and nectarine trees: there's always spraying Liquicop combined with a spreader-sticker, followed by covering the trees with a row cover such as Agribon or other medium weight row cover fabric during rainy weather. Be sure to remove any covers during sunny weather to avoid overheating problems.

Ingels does pass along this tip: "Agribon likely allowed some rain to penetrate to the branches. It may be best held up with a post in the middle to allow rain to run off down the sloped sides rather than having a flat surface on top, but it must be fastened securely because of strong winds."

Monday, November 5, 2012

National Fig Week? Homemade Fig Newtons!

According to Sacramento's main promoter of supermarket fruits and vegetables, Michael Marks, this week is National Fig Week. It seems a bit late in the fig season to be celebrating this under-utilized fruit, but what the heck...anytime is a good time to enjoy figs, fresh or dried! 

Fig images courtesy Dave Wilson Nursery

Figs are part of a heart-healthy diet. 3 to 5 dried or fresh figs provides 3.5 grams insoluble fiber and 1.5 grams water-soluble fiber. Diets rich in soluble and insoluble fibers, such as the fiber found in figs, help maintain healthy blood cholesterol levels.

 The fruit from the most popular home fig tree varieties are usually harvested around here in September and October. Still, some of you may have a few figs lurking on your backyard trees.

I enjoy fresh figs as part of a fruit salad. For those of you who want the occasional sweeter treat, eaten in moderation, you may enjoy this recipe for:

Homemade Fig Newtons

For the Filling:
1 lb. dried figs or 2 lbs. fresh figs
1 cup sugar
1/2 or 1 cup water (1 cup for dried figs; 1/2 cup for fresh)

Dice figs, soak in water 1 hour.
Add 1 cup sugar & cook on medium heat until it has a thin jam consistency.

For the Pastry:
1/2 cup butter, room temp.
1 cup sugar
1 egg
1 tablespoon cream or milk
1/2 teaspoon vanilla

Beat 1 cup sugar, butter, egg, milk & vanilla until well blended.

Then add these to the pastry mix:
1/2 teaspoon salt
1 teaspoon baking powder
1 3/4 cup flour

Mix well and refrigerate for 1 hour.


Place 1/2 of the pastry on well floured dough cloth; knead about 6 times.
Roll out pastry to 1/4" thick. 
Line the inside of the 13 x 9" glass dish with the rolled pastry; cover that with fig filling.
Roll out remaining pastry, and cover the fig filling in the glass dish. Cut off any excess pastry dough.

Cook at 350 degrees for 30 minutes.
Let cool and cut into squares.

Thursday, November 1, 2012

November Frosts, Freezes Ahead? Probably.

 The typical Sacramento-area frost season (when temperatures dip to 32 or below for short periods of time) is fairly short: primarily, December and January.

However, November frosts do happen here with regularity. Freezes, too.
The earliest frost date for Sacramento was on a November 4, back in 1935, when the morning low fell to 30 degrees. The latest frost date recorded was on March 27, 1898, with a low of 32.
In 2011, a surprise cold snap on the morning of November 5 sent some areas in Sacramento County to freezing.

 Two years ago, there was a 2010 Thanksgiving surprise: the morning low temperatures in the suburbs of Sacramento dipped into freezing territory. 28 in Elk Grove. 24 in Rancho Cordova. 23 in Folsom. The temperatures in Rancho Cordova and Folsom stayed below 28 degrees for 7 hours that morning. That's a citrus-killing, perennial-punching hard freeze.
Freeze-Pummelled Pummelo

Not a Happy Hosta Thanksgiving

What is cold? Some definitions:

Frost: temperatures dip to 32 °F (0 °C) for short periods of time. Occurs with fair skies and light winds.

Freeze: temperatures at or below 32 °F

Hard Freeze: temperatures below 28 °F for several hours.

 Fruit-laden citrus trees could be threatened by very cold mornings in the weeks (or days) ahead. Some planning tips for the upcoming cold mornings:

Before a frost:
• Identify cold spots in landscape by monitoring with a thermometer that registers high and low temperatures.
• Identify plants at risk: citrus, succulents, tender perennials, tropical and subtropical plants.
• Have supplies ready: sheets or frost cloths, lights, wraps for trunks, thermometers, stakes or framework to hold covers off foliage.

• Prepare tender plants: avoid fertilizing and pruning after August to minimize tender new growth. 

• Plant insurance: In September and October, take cuttings from frost sensitive perennials; keep cuttings in a sunny, indoor area.

• Rake away mulch to allow soil to warm up during the day and radiate heat at night into plant.

• Monitor weather forecasts and note how low temperatures will be and for how long. 

Pipe Wrap: Cheap Frost Insurance

When a frost is forecast:
1. Move potted plants to a warmer spot next to house or under patio cover, especially on south side.

 2. Check that plants are well-watered since dry plants are more susceptible to damage, and moist soil retains heat better than dry soil.

3. Cover plants with a row cover before sunset to capture ground heat radiating upward at night, but remove covers daily if it is sunny and above freezing to allow soil to absorb heat.

4. Add heat by using outdoor lights: hang 100 watt drop lights or Holiday string lights to the interior of the plant. Use the old C7 or C9 large bulbs, not new LED lights which do not give off heat.

5. Wrap trunks of tender trees if hard freeze is expected, using towels, blankets, rags, or pipe insulation.

6. Harvest ripe citrus fruit. Generally, both green and ripe fruit are damaged below 30 degrees, but there is some variation by species (refer to the chart in UC/ANR Publication 8100, "Frost Protection for Citrus and Other Subtropicals").

7. Winterize your gasoline-powered garden equipment. Gas can go bad and screw up your engines if allowed to overwinter, unused. Drain the tanks or turn off the supply valve and run the engine until it stops. For containerized gas (or gas still in equipment) add a stabilizer. Run the engine for 10 minutes or so to make sure the stabilized gas is thoroughly mixed into the engine.

When a Freeze or Hard Freeze is Forecast (temperatures remain at or below 28 degrees for several hours)

1. Wrap any exposed plastic water pipes; use a cover for outdoor faucets. Turn off the water supply to outdoor irrigation faucets, if possible. Allow those faucets to drain.


2. Disconnect garden hoses and lay them out straight...away from driveways!

3. Adjust your pool, spa or pond filtration timers so that they are running when the chance of freezing temperatures is greatest, between two and nine a.m. Moving water is less susceptible to freezing.

4. For dish-shaped fountains: Turn off and let drain to the holding tank below ground. Remove any standing water in the dish.

Frosty the Fuchsia
After a frost:
1. Identify damage: dark brown or black leaves and twigs.

2. Wait to prune out damage until after danger of frost is past, and new growth begins in spring.

3. Make sure the backyard birdbath isn't frozen over in the morning. Daily fresh water for dogs and cats is also a good morning habit.