Garden Talk: October 7, 2013

From NGA Editors

Pick a Perfect Pumpkin

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Whether for fall decorating, delicious pies, or Halloween Jack-'o-lanterns, October is pumpkin time. If you're growing your own, how do you know when your pumpkin is ready to pick? And if you're selecting one from a local farmers market or vegetable stand, what should you look for to choose the best?

Home gardeners should harvest pumpkins when they are fully colored and their outer rinds are thick and tough enough that they can't easily be pierced with a thumbnail. But be sure to pick pumpkins before the first heavy frost. Otherwise they can suffer chilling injury that will keep them from storing well. Cut, rather than pull, pumpkins from the vine, leaving several inches of stem attached. But never carry a pumpkin by its stem. If its stem breaks off, the pumpkin won't keep long.

Select only the best specimens for storage, without bruises, cuts, or soft spots. For the longest storage, cure your pumpkins to dry and harden their shells completely. Place in a warm (75-85 degrees F is ideal), well-ventilated spot for a week or two -- perhaps near your furnace or on an enclosed porch. After curing, store pumpkins a cool, dark spot (50- 60 degrees F), such as an unheated spare room or cool closet. Check them periodically and remove any that show signs of rot.

If you're choosing a pumpkin for carving, take the advice of University of Illinois Extension horticulture educator Ron Wolford and select one with a lighter orange rind. These are easier to carve than darker orange varieties because the skin is not as hard. (The lighter varieties don't keep as long in storage, however.) Use the thumbnail test described above to make sure your choice is fully mature and check to see that 1-2 inches of stem is still attached. After carving, Wolford suggests coating the cut surfaces of the Jack-'o-lantern with petroleum jelly or vegetable oil to prolong its decorative lifespan.

If pie making is your goal, select a variety bred for sweet, tasty flesh, not size, such as 'Small Sugar’' and 'Baby Pam'. These smaller varieties have smoother, denser flesh with a higher sugar content than the large varieties bred for carving and decoration. In addition to its delicious taste, bright orange pumpkin flesh is high in fiber, low in calories, and loaded with healthful beta-carotene.

To find out more about pumpkins, including their history and lots of interesting pumpkin facts, check out this great resource from the University of Illinois Extension at Pumpkins and More.

2013 American Garden Award

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All-America Selections has announced the winners of this year's American Garden Award, now in its fifth year. The 2013 American Garden Award featured four new flower varieties chosen by their breeders for their excellent garden performance. Once these new varieties were planted and put on display at the thirty-one participating gardens across the U.S. (and in Quebec), the public was invited to vote for their favorite using one of several voting methods. The votes have now been tallied and the three winners chosen.

The Grand Prize winner was the eye-catching Verbena 'Lanai® Candy Cane'(pictured). Its truly unique flower pattern really commands curbside attention! This striking red-and-white striped beauty offers continuous summer blooms and superior weather tolerance.

Second place honors went to Zinnia 'Zahara™ Cherry'. Loaded with deep red, single blossoms, this fast-growing zinnia blooms continuously all season long and is both disease and drought tolerant, making it a great choice for both containers and landscape beds.

Last, but not least, is third place winner Impatiens 'SunPatiens® Compact Electric Orange'. With vibrant, deep orange blooms, 'Electric Orange' is a new color in the SunPatiens® line. SunPatiens fill in quickly, providing three seasons of color in the garden and in containers. They can be planted in sun or shade and are trouble free.

For more about American Garden Award winners, including past winners, go to American Garden Award.

Coping with the Emerald Ash Borer

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The emerald ash borer (EAB) is a small insect that is causing some big problems. Accidentally introduced into the U.S., this Asian native is thought to have arrived in wooden packing materials brought in by ship or air. Since its discovery in southern Michigan in 2002, it has cut a swath of destruction as it has steadily expanded its range. So far this damaging pest has killed tens of millions of ash trees in twenty-one states and two Canadian provinces. Many more trees are at risk if this invader is not contained.

What can you do to protect your ash trees if you live in an area that's been invaded? There are some insecticidal treatments that can be done on healthy ash trees in street and home landscape settings that can help protect them from infestation. To help homeowners and municipalities decide on the best preventative treatment options, Iowa State Extension has put together a newly revised, free, downloadable publication detailing current emerald ash borer management options. While written for Iowa homeowners and tree care professionals, this publication has information that tree owners in other states where the borer is active will find helpful. Consult with your local Extension Service for more advice specific to your state.

Iowa Extension's recommendation is to treat trees only if they are within 15 miles of a known EAB infestation. If you are outside this risk zone, continue to monitor the location of confirmed outbreaks in your state. If you live within a risk zone and decide to treat your tree, they recommend using trunk injection or soil injection or drench done by a commercial pesticide applicator, or a soil drench or granules applied by a homeowner according to label instructions. They do not recommend canopy sprays because these are less effective and more likely to harm non-target organisms.

Also available to help you decide if symptoms on your ash tree are due to EAB or some other problem is another downloadable publication on the common problems of ash trees. Amply illustrated with many clear photos, this will help you figure out if your tree is an ash, and shows you symptoms of EAB infestation, as well as those of problems that can be confused with EAB.

To download both these helpful publications, go to Iowa State University Extension.

The Impact of Climate Change on Colorful Fall Foliage

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New England hillsides are beginning to blaze up in their much-anticipated seasonal display of reds, oranges, yellows. Unfortunately in the Northeast and other parts of the country, this autumnal show may not be as spectacular in the future, as global climate change disrupts weather patterns.

While maples may still don their fall colors, the change may happen later in the season, and the red leaf hues could be duller as the climate warms, according to Howie Neufeld, professor of plant physiology at Appalachian State University in North Carolina.

A 22-year observational study at Harvard Forest in Massachusetts showed that the fall foliage color change there now occurs three to five days later, on average, than it did at the beginning of the study. This might not seem like much, but if the pattern continues, the timing of color change could shift to well over a week later by mid-century, according to Harvard emeritus professor John O'Keefe, who collected the data.

Cool fall nights and decreasing day lengths are a signal to trees manufacture anthocyanins, the red pigment that colors fall leaves. If nights remain hotter as the climate warms, this process may be disrupted, resulting in less colorful foliage. If droughts become more pervasive, as many climate change models predict, stressed trees may simply shed their leaves early with any color change. Perhaps the biggest worry is that climate change will make conditions unsuitable for trees such as sugar maples, forcing them to migrate north to survive. None of the more southerly species that might move in to replace them have the brilliant fall colors that maples display.

To read more about why autumn leaves may be dulled by climate change, go to Vermont Invasives

 
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