Question
I live in the realtively hot inland valley of Southern California(Rancho Cucamonga) and I planted three "Tuscarora" crepe myrtles from 24" boxes about 2 years ago. Since then I have noticed during hot weather the leaves seem to wilt when they are not watered at least once a week.
Now during a long hot spell I have been watering them several times a week. I don't see any insects or aphids on the tree but the leaves on one tree especially seems wilty for several weeks now.
Can you over water a crepe myrtle tree ?

Answer
Kevin,
I do not think that under the conditions that you are describing, that you can overwater the trees. What I feel instead, is that you have started to increase the frequency of the watering, causing the roots to come up towards the surface. This creates a high root system that is more suseptible to drying out.
When you water, you should be doing it for a long period, on an irregular schedule, to develop a deep root system that will seek out water on it's own.
I would recommend fertilizing the trees to help the survive, using a low nitrogen fertilizer. Continue watering on an irregular schedule for 45 mins to 1 hour, this ill allow the water to penetrate deeply into the soil.
Good luck.
Ed Gulliksen