Question
I have several Tuscarora crape myrtles that are about 10 years old. All are spaced well apart and receive ample sunlight most all day. All have done well and have never been "topped", only the suckers along the bottoms have been removed to encourage them to be tall bushes. Three years ago, two of them ( side by side ) started to die on various limbs. These were trimmed heavily at the end of the year and started vigorous growing the following year. Alas, the problem came back. A third bush in the same group has no problems. When the problem reoccurred, the two bushes were dug up and discarded in the burn pile. Now a third bush completely remote from the problem two is showing the same symptoms. Limbs dying from the top. I see no insects, I see no powdery molds. Yes, we are in a terrible dry spell but I started watering the problem bush early in the year with a soaker hose and it continues to slowly die. Others ( maybe 15 bushes the same age and origin ) have no problems. Any ideas?

Answer
Hi Charles,

I'm not sure exactly where you are in Texas, but no doubt it's been hot and dry.  I do not think that your problem sounds like a pathogen.  Crape myrtles are relatively disease free and the problem you are describing is more typical of environmental stress than a disease caused by a pathogen.  Dry weather is highly unfavorable for plant pathogens and most of them manifest themselves in obvious ways (leaf spots, nasty cankers, rapid death and decline).  At temperatures above 95F, not many plant pathogens are active.  If you should find any cankers or any unusual discoloration in the wood, please take a picture and I can try to help you identify it.  However, I really think the problem is typical of environmental stress.  

I would suggest that you verify that your watering regiment is adequate.  Use a shovel and dig down to confirm that the soil is actually wet down to at least 8 inches.  Often, just the surface is watered and not the deeper roots.  It is best to water deeply (8-12 inches down) one or two times a week as opposed to light and more frequent watering.

The problem with the individual tree problems may be site related.  The soil type may be slightly more compacted in some areas or the nutritional situation may have changed over the years.  

It may be helpful to have a new soil test done on your trees.  This will verify that the soil pH is correct and allow you to properly add nutrients to the soil.  You can generally have your soil tested through your local county extension office.  If you visit the Texas Agrilife Extension Service website (http://agrilifeextension.tamu.edu/), you can find the location of your local office.  They will also be listed in your phone book.

Good luck!