Issue: July 8, 2006

Chitalpa lost leaves in summer

I have a multi-trunk chitalpa that I planted just over two years ago. It has grown well and nearly doubled in size since I planted it. About 10 to 14 days ago, I noticed that leaves on one of the trunks began to wilt. I thought that someone may have sprayed an herbicide or other chemical in the alley and that some spray-drift hit that part of the tree. After about 3 to 4 days, symptoms appeared on another part of the tree. After another 3 to 4 days, the last part began to show the symptoms.

I have spoken to some individuals at local nurseries. One said that if it was "drift" I should water it with a lot of water. I did this about the time the second portion started to show symptoms. Since then, I have lost the last two parts. Another person suggested that I reduce the watering. He thought my tree was overwatered. I have also lost the last trunks since watering about a week ago. The tree is now dead or dormant-looking, and I am not certain if it will come out of this. I'm hoping new growth will appear.

Do you have any suggestions as to what I can do to save this tree, or do I just wait to see if it comes out of its "illness"?

There are several potential reasons for the problems with your tree. It is not uncommon for chitalpa trees to exhibit mid-summer defoliation. However, they don't usually drop all their leaves. The typical symptom of mid-summer defoliation is scorching of leaves and loss of many (but not all) leaves. After monsoon rains arrive, they often refoliate. If dry weather returns after the monsoon, the leaves may again scorch before dropping in the autumn. Since your tree is completely defoliated, there may be another factor involved or the trees were just not watered enough. Last winter was extremely dry and may account for severe symptoms. Now that the monsoon season has arrived, look for refoliation.

Chemical misapplications (as you suspected) may be a cause as well. Spray drift from a neighbor's chemical application is one possibility. If you were aware of spray reaching your tree and had washed the chemical off immediately, you might have avoided problems. This would be effective if the chemical was absorbed only through leaves and not roots (had no soil activity). However, by the time symptoms appear, the chemical has been absorbed and it is too late to wash the chemical off.

If the chemical was soil active (absorbed by roots), then washing it off would require a lot of water. If it was only just washed off the leaves and not away from the plant, the roots could absorb it, and then the problem would develop anyway. If a neighbor had applied a soil active herbicide which was followed by a heavy rain, the chemical may have washed into the root zone of your tree.

Other chemicals may also cause problems. If insecticides were applied to control aphids or other insects, they could cause defoliation as well. Even insecticidal soap or horticultural oil can cause burning in the heat of summer. If that is the case, the leaves should redevelop. If the problem is herbicide, the tree may not be able to survive.

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For more gardening information, visit the NMSU Extension publications World Wide Web site at http://www.cahe.nmsu.edu/pubs/_h.

Send your gardening questions to:
Yard and Garden, ATTN: Dr. Curtis Smith
NMSU Cooperative Extension Service
9301 Indian School Road, NE, Suite 112
Albuquerque, NM 87112

Curtis W. Smith, Ph.D., is an Extension Horticulture Specialist with New Mexico State University's Cooperative Extension Service. New Mexico State University is an equal opportunity/affirmative action employer and educator.