June 17, 2006

Save the Dates

July 29th -- Chef Cathal Armstrong from Restaurant Eve

Aug 19th -- Bart Seaver from Café Saint-Ex

A family picnic to benefit Farm Aid Saturday June 24, 2006 from 1 to 4 PM.

Bring your kids and help the next generation understand why we need family farms and the role they play in our food system. Among the events are from 2 - 3 pm a family picnic dinner to celebrate the connection between quality food and the family farms on which it is grown. Buffet syle dinner will feature farm-fresh dishes prepared by celebrated DC area chefs.

List of chefs, other events, and ticket information is available at: http://www.farmaid.org/site/PageServer?pagename=e quinox&JServSessionIdr002=52tn6n8p03.app6b

Monica Lear, Arlington/Alexandria Horticulture Extension Agent, offers the following as you consider your current plants, and think about what to plant next. And remember VCE Master Gardeners are available every Saturday in the summer 8 to 11 to answer your lawn, garden and tree care questions.

Winter Injury on Woody Ornamental Plants

Winter injury may result from several environmental factors: late spring frosts, dramatic temperature fluctuations, unusually warm midwinter temperatures, extended periods of extreme or abnormally cold temperatures and drying winds. It is particularly damaging to ornamental plants that have tissues that are not mature or have not entered dormancy. Winter injury predisposes and weakens plants and makes them more susceptible to injury by weak pathogens. Often, symptoms are not evident until some time after the injury occurs. This makes can make an accurate diagnosis difficult.

Winter injury symptoms are variable and take many forms. Common symptoms are tip and branch dieback, foliar browning, winter desiccation, sunscald or sunburn, and frost cracks.

Tip and branch dieback occurs if temperatures get too low in winter or from frosts in early fall or late spring. It is usually aggravated if a warm period is followed by an extremely cold one. Buds or entire shoots may be killed. Buds may also be sufficiently damaged to allow entry of disease-causing fungi. Flower buds are more cold tender than leaf buds and may be killed while leaves are unaffected. This type of winter injury is more severe in non-adapted or marginally hardy cultivars. Symptoms first become evident in spring when plants fail to flower or leaf out. When the new growth finally begins, shoots arise from the older parts of the branches. Sunscald or sunburn occurs in late winter when the sun is bright. Sunscald usually occurs on the south or southwest side of a tree. Thin bark on the tree is warmed enough to become active. When temperatures fall sharply at night, the inner living bark is killed. Young, thin barked trees are more susceptible to sunscald. Frost cracks develop from internal stresses in the tree trunk. Frequently these cracks open up in coldest weather and close again when the weather warms up. Cracks may open in the same place year after year resulting in a callus ridge down the side of the tree. As long as the tree is otherwise healthy, frost ribs do little harm, but if the tree also has heart rot or is hollow, they may constitute a serious structural weakness.

The following are ways to reduce winter injury:

Select plant materials that are native or winter hardy for your area.
Select a site that provides some protection from damaging winter winds.
Avoid poorly drained soil or low spots that create frost pockets and sites that are likely to experience rapid fluctuations in temperature.
Place plants away from house eaves and other snow or ice collecting areas where snow or ice is likely to fall or slide onto the plants.
Follow recommended cultural practices to keep plants healthy.
Proper pruning at the appropriate time is important in reducing damage by ice and snow. Avoid late summer pruning that stimulates new, tender growth and reduces the supply of nutrients available to the plant through winter.
Give plants a deep soaking that will supply water to the entire root system before the ground freezes. Watering during the winter on warm days is also important.
Use a 2 to 4 inch layer of mulch to reduce water loss and reduce the alternate freezing and thawing of the soil that can cause some shallow rooted plants to heave out of the soil.

Sources: Virginia Tech Extension, UConn Extension Service