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4-3-03
Question and Answer
Q. My peonies are turning brown where the stalk meets the ground, causing
the stems to fall down. Some of the leaves are wilted, and the buds never
open. This has happened for years. I don't see any insects. -- Don Walker,
Nashville, Ind.
A. Botrytis blight causes the symptoms you have described and can also
cause a gray mold to form around the base of the stalk. Wind and insects
carry the fungal spores.
Sanitary measures offer the most effective means of control. Start with
a thorough cleanup of old, infected stems and leaves and other plant debris
in the fall. This reduces the overwintering site for the fungus. Pull
the soil away from the crown without injuring the buds.
In the spring, remove and destroy any wilted or rotted shoots as soon
as you detect them. If mulch or another covering is used for winter protection,
remove it in the spring before the new shoots emerge from the soil.
Improving air circulation and penetration of sunlight to peony plants
often solves the problem. Sometimes, however, chemical control is necessary.
If so, spray with a fungicide labeled for botrytis blight when new shoots
appear in the spring. Follow label instructions. Thoroughly soak the surrounding
soil. Repeat the procedure a week later and again when the shoots are
3-6 inches tall.
Q. It seems like annual plants, like Christmas decorations, are available
earlier and earlier each year. Is it OK to buy them so early? -- Linda
Todias, Merrillville, Ind.
A. Researchers keep records on weather patterns and have developed maps
that predict, on the average, when you may expect the last 32 F freeze
of the spring and the first frost of the fall. At the time of your frost
date, you have a 50 percent chance of a freeze. Planting before that date
just means the odds are greater that the plants will suffer from a freeze.
You can protect a small number of plants with floating row covers, upside-down
bushel baskets or other protection, but it isn't wise to risk large, expensive
plantings when the odds of a freeze are against you. You're best off to
wait until the chance of freezing drops.
Your frost-free date can be found by calling the Purdue Extension office
in your county or by consulting "Effects of Cold Weather on Horticultural
Plants in Indiana," available online at http://www.agcom.purdue.edu/AgCom/Pubs/HO/HO-203.html.
Retailers count on us chomping at the bit for spring's arrival. We, anxious
for the end of winter, provide the demand so they, looking for increased
sales, provide impatiens and petunias in early April. We're best off to
purchase cold-tolerant annuals like pansies or ornamental kale at that
time of year!
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