Japanese maple, a spring beauty, may now be dying of thirst

Backyard Q&A

July 07, 2002|By Dennis Bishop | Dennis Bishop,Special to the Sun

Q. Our Japanese maple was beautiful this spring, but now the tips of the leaves appear to be dying. Do you know what would cause this?

A. Japanese maples are outstanding trees for the landscape and have very few disease or insect problems. However, they are subject to leaf scorch. Leaf scorch is a physiological problem, not a disease. It occurs when the leaves lose water faster than it can be replaced. If your tree is planted in full sun or in a windy location, it will cause the leaves to dry rapidly, and that may be the primary cause of the problem. On the other hand, your tree's roots may have been damaged by recent droughts, and they may be unable to take up enough water.

In either case, water is the key. I would give your tree a slow, deep watering, and I would repeat the watering during dry spells of summer and fall. If your tree is planted in a hot, dry site, you will need to maintain this watering regimen through every summer and fall. If the roots were damaged by drought, it will take them several years to recover. After that time, you may be able to water less frequently.

Q. In an earlier column, you wrote about the hemlock wooly adelgid and described it as a "serious pest of hemlock." Do you still recommend hemlock trees for landscape planting? What can be used as a replacement?

A. This adelgid is a very serious pest, and we generally do not recommend planting hemlocks.

Hemlocks are somewhat unique in several ways and are difficult to replace in the landscape. For example, they will grow in shade better than any other tall evergreen tree. Also, they have a soft and graceful nature that is not found in other evergreen trees.

I would select a replacement depending on the location and the intended function of the trees. If you are looking for a tall evergreen, there are several spruces and pines that might work. Or you could plant a Southern magnolia. If a smaller evergreen will do, I would try American holly.

Dennis Bishop is an urban horticulture educator for the Baltimore office of the Maryland Cooperative Extension Services. 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.


1. Yews and boxwoods have completed most of their growth for the year. They can be pruned now and may not need any additional pruning during the summer.

2. Most garden mums like to bloom in late summer. To delay blooming until fall, pinch back the plants now and remove the emerging flower buds. New buds will grow to produce fall blooms.

3. Are you planting second-crop vegetables now? Use row covers to protect them from the searing sun.

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