Garden Talk: February 10, 2011

From NGA Editors

Half a Plate of Produce

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"Make half the food on your plate fruits and vegetables." Following this tip is an easy way to bring your diet in line with the USDA's recently released Dietary Guidelines for Americans, 2010. The USDA recommends that we all increase our intake of vegetables and fruits and include a wide variety of vegetables, especially dark green and red and orange vegetables and peas and beans.

Growing your own is an economical way to fill your plate with fresh, healthful, great-tasting fresh produce. Here's a suggestion from the National Garden Bureau for a new variety to add color and nutrition to your garden and your diet this season.

'Celebration' Swiss chard from Chriseed offers a kaleidoscope of color to your vegetable patch; in fact, its multi-colored stems are so attractive you may decide to add this chard to your ornamental garden as well. It produces uniform, 10-inch tall plants with deep green leaves and vibrantly colored stems in shades of pink, orange, and yellow. It's ready in just 30-33 days to harvest as baby chard; mature plants take 50-60 days from seed.

Sow seeds 1/2 inch deep and 2-4 inches apart in spring, beginning about 2 weeks before your last expected frost date, making repeat sowings through the season. Gardeners in hot summer areas may need to take a midsummer break, but chard makes a great fall crop once the weather moderates. When seedlings develop their first set of true leaves, thin to one per cluster using small scissors to clip out the extras at soil level; thin again when plants are 4-6 inches tall, spacing them 6-12 inches apart, depending on whether you plant to harvest baby or mature plants.

For more information on 'Celebration' Swiss chard, go to: National Garden Bureau. For more information on USDA Dietary Guidelines, go to: USDA.

Killing Weeds Organically

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Many gardeners prefer to steer clear of chemical herbicides, yet are looking for ways to make weed control easier. There are a number of organic herbicide products on the market these days. Are these products effective or should you stick with hoeing or hand weeding?

W. Thomas Lanini, weed ecologist for the California Cooperative Extension Service, recently investigated the effective of a group of organic herbicides that are all contact herbicides with no residual activity. The active ingredient in these products was either acetic acid (vinegar) or various plant oils that work by stripping away the waxy cuticle on the leaves, causing them to wilt and dry up. They included WeedPharm (20% acetic acid); GreenMatch (55% d-limonene, which is the major component of the oil extracted from citrus rinds); GreenMatch Ex (50% lemongrass oil); Maratec (50% clove oil); and WeedZap (45% clove oil and 45% cinnamon oil).

As detailed in an article in the January/February 2011 issue of TPI Turf News, Lanini found that these products gave reasonably effective control of broadleaf weeds such as pigweed if weeds were treated when they were still young. In his study, treatment 12 days after weed emergence gave anywhere from 100% to 61% control; waiting until 26 days after emergence brought the percentage of control down to 0% to 38%. Organic herbicides were much less effective on grassy weeds, most giving about 25% control on 12 day old weeds and virtually no control on 26 day old ones.

He also found that good spray coverage was essential and that adding organic surfactants or spreaders to the herbicides improved control. Most of the organic herbicides also worked best at temperatures above 75 degrees.

For more information on the evaluation of organic herbicides, go to: Organic Herbicides.

Vulnerable Viburnums

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In the early 1990s, a previously unknown fungus-like organism called Phytopthora ramorum was discovered infecting rhododendrons and viburnums in parts of Europe. Then this same organism was discovered in the U.S. causing the new disease "sudden oak death" in the San Francisco Bay area. In the years since, it has spread to various locations in western North America, infecting not only oaks and tanoaks, but over forty species of ornamentals, including viburnum, rhododendron, camellia, pieris, mountain laurel and honeysuckle.

On viburnums, ramorum blight causes leaf blight and shoot dieback; severe infections can kill plants. Recently, Timothy Widmer of the Foreign Disease and Weed Science Research Unit of the USDA Agricultural Research Service evaluated twenty-four species or cultivars of viburnum to assess their susceptibility to this emerging disease threat.

The results of the study showed a wide range of vulnerability. The most susceptible plants tested were Viburnum x carlcephalum 'Cayuga' and V. tinus. The most tolerant were V. x rhytidophylloides 'Willowwood' and V. opulus 'Notcutt.' In this study, above-ground parts of the plants were inoculated with the disease-causing organism, in contrast to previous studies using detached leaves. This is important because, while the individual leaves of some viburnums show extensive necrosis when they are infected, some of these same viburnums show the fewest number of infected leaves overall. In general the evergreen species and cultivars were more susceptible to infection than deciduous ones.

While no one yet knows whether this disease can be contained or how far it may spread geographically, if you are in or near an area where ramorum blight has been found, it may be a good idea to choose the most resistant species or cultivars when planting viburnums in the landscape.

For more information on the susceptibility of viburnums to Phytopthora ramorum, go to : ARS.

Get Ready for Hijinks this Halloween

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Halloween, that holiday of tricks and treats, may seem a long way away as winter cold and snow still covers much of country. But it's not too early to be planning your hijinks -- in the form of pumpkins, that is!

A 2011 All-America Selections Vegetable Award winner, 'Hijinks' pumpkin will make a great contribution to your Halloween fun. Producing small, uniformly sized and shaped, 6 to 7 pound fruits, this variety has smooth, deep orange skin with distinctive grooves that make it great for fall decorating, carving, or painting. Bred by Sakata Seeds, it is a high yielder with excellent resistance to powdery mildew. Other attributes that make this variety a winner are strongly attached stems and easy removal of fruits from the vine.

The vines can grow up to 15 feet long, so give 'Hijinks' plenty of room, allowing 10 feet between rows and 2 to 3 feet between plants in the row. It's ready in 100 days from direct seeding; 85 days from transplant.

All-America Selections winners are new garden seed varieties that have been judged to have superior garden performance in impartial trials in North America.

For more information about 'Hijinks' pumpkin and other AAS 2011 award winners, go to All-America Selections.

 
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