Q - Our beautiful Japanese yews are slowly but surely going bad. We have them planted along with the azaleas in front of the house. They're not getting any new growth. What might be wrong?
A - Yews prefer a neutral soil, neither acid nor alkaline. When the soil gets too acid, they start to hurt. In all probability that's what's happened. They are not good companions for azaleas, which require an acid soil.
Q - Many of the leaves are dropping off our sycamore trees. Isn't that abnormal this time of year?
A - The common sycamore, so widely planted in many areas, is very subject to a fungus disease called anthracnose during cool, damp spring weather. The leaves turn grayish-brown, then fall to the ground. This spring conditions have been nearly perfect in some areas for the fungus to thrive and cause a heavy loss of leaves. There is no practical way to prevent the disease. The trees will appear ragged for several weeks but usually put out new leaves and recover. It's a good idea to rake up and destroy the fallen leaves.
Q - Is there such a thing as a warm-season lettuce? If there is, I'd like to plant some.
A - Lettuce is a cool-season crop and can be grown in both spring and fall. Buttercrunch and Grand Rapids are two loose-leaf types that will tolerate some heat.However, none will grow satisfactorily in midsummer.
Q - Will mothballs keep dogs away from my shrubs?
A - Do not use them. They will not repel dogs and are poisonous to small children who might find and put them in their mouths. Dog repellants are for sale at some large garden centers, but they usually lose their effectiveless after the first heavy rain.
Q - If I leave the faded flowers on my phlox plants and get seed, will the seed be any good?
A - The seed that develop on hybrid plants will not come true and are therefore undesirable. Removing the faded flowers helps the plants conserve energy for new growth and they may bloom again in the fall.
Q - I've tried almost everything to grow grass under my Norway maple. What variety might be successful?
A - Generally, it's a losing battle to try to grow grass in rather heavy shade. There are no known varieties that will survive for long in such an environment.
If you have a question for Tom Stevenson, write to him at
The Washington Post
1150 15th St. NW
Washington, D.C. 20071.