I can't think of any fungus problem that would cause that kind of symptom. My first gut reaction is that it is some sort of response to stress of some sort.

Let's see a picture of the whole tree and one of the trunk, including the base where it's growing from the ground.

looks like my bradford pear when it is stressed for water.

it was here when i moved in. every summer when have triple digit weather and no rain it looks just like that crepe myrtle. i just dug up a crype myrtle and planted roses in its place. that is diffentily drought stress. you ever put a soaker hose and give it a good two hour soaking?

I am having the same problem with my Natchez right now. I was wondering if it could be caused by poor drainage.

not without pix.. ken

dhohorst this happened to me, and then the tree bloomed pink. The nursery sold me the wrong varietal of crepe myrtle.

It wouldn't be the first time for me either. Really scary when the nurseries don't have a clue what they have. Of course, every time it happens it involves Lowes - go figure. I eagerly await the blooms and hope it is just in need of some fungicide.

Did your Natchez crepe myrtle with the red leaves ever grow and bloom the way it was supposed to? I planted 5 new natchez crepe myrtles, and the same thing is happening now! A couple are brownish-red, and the others are bright redish leaves... I think it might be because they are getting too much water, but I don't know if I should just return the plants and get new ones... I really like the natchez variety!