If leaves have died but not fallen, American elm may be diseased

Backyard Q&A

October 20, 2002|By Dennis Bishop | Dennis Bishop,Special to the Sun

We have a large American elm in our front yard that began dropping leaves in mid-September, and we are concerned that it may have Dutch elm disease. How can we tell?

Dutch elm disease is a fungal disease that is spread from tree to tree by small beetles in the spring. Sometimes infected trees will decline very rapidly, but in other situations trees may live for months. There is no cure. Typically, the first symptom you see is flagging branches, on which all of the leaves have died, but they continue to hang on.

If your tree has one or more flagging branches, you should be concerned, and I recommend that you call a certified arborist to inspect your tree. The arborist can confirm whether your tree is diseased and can determine if the tree needs to be removed.

On the other hand, if your tree is dropping some leaves throughout its entire canopy, you should not be concerned. This is probably caused by stress related to the drought we have suffered.

I planted some glossy abelia shrubs along our front foundation three years ago, and they looked great. Now they are somewhat ragged. How should I prune them?

If a shrub has a few long, scraggly branches that are particularly out of character with the rest of the plant, I would prune those out now. Your plants will then look fairly good this winter.

However, I would not do any serious pruning until late winter or early spring. Because glossy abelia flowers on new wood, you can prune them in late winter without removing any flower buds. And even if you prune them very hard at that time, they will develop new branches and a nice full top during the spring and summer.

Do not top or head back glossy abelia. They will never look good after being pruned in this manner. You should always remove whole branches, preferably from the base of the plant. Start by removing any dead or diseased branches, and then some of the oldest branches to rejuvenate your plants.

Dennis Bishop is an urban horticulture educator for the Baltimore office of the Maryland Cooperative Extension. If you have a gardening or pest problem, you can call the Home and Garden Information Center hot line (Monday through Friday, 8 a.m. to 1 p.m.) at 800-342-2507. You can also e-mail questions, order publications and diagnose plant problems by visiting the Web site, www.hgic.umd.edu.

Checklist

1. Hibiscus trees are somewhat hardy, but will not tolerate frost. They should be brought indoors for the winter, before the first frost.

2. Shred fallen leaves with a lawn mower or string trimmer to hasten the breakdown process. Do not allow leaves to cover your grass over the fall and winter.

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