Mine are doing this as well as are many around town. I checked for sooty mold aphids and all the usual problems on mine and none exist. As you probably know, they grow on the side of roads in public plantings with no care. I'm not sure, but I don't think the leave drop will harm the trees permanently. Absent some disease on your tree, I think they are just early losing their leaves. We had a really weird spring - record low temperatures for several weeks (ten degrees below average) followed by record heat (ten degrees above average) for several weeks and no rain. I have had a lot of plants off schedule because of this. (My squash plants planted in early march just started producing fruit and the mexican petunias and perennial hibiscus were a month late starting to bloom.) I also have noticed it is significantly cooler at night than normal for August and the daytime highs many days have been more like September weather.

You might want to check out Cercospora lythracearum - It is a fungus that causes the leaves to turn yellow and drop. I might investigate this as well.

Ah! Mexican petunias!! I left hundreds of them in my old yard! Gave so many away as they run like mad. I hope that I can find some here! This yard is huge but absolutely nothing but grass, so I can hardly wait for fall to come so I can start making beds! I'll look up that fugus you mentioned. Thanks

I could send you some seeds of the pink tall and purple tall variety if you email me to remind me. I think you will find that you can grow almost everything you could in Florida zone 8. I live in Thibodaux about an hour and a half east from you and about ten miles from the southern line of zone 8. I get into the low twenties seven or eight nights a year. They biggest challenge for me is that the soil ph is alkaline which makes azaleas, camellias and gardenias difficult and that some plants require decent drainage which requires raised beds. You are very close to Stokes Tropicals which has a nice nursery in Jeanerette. Also, there are a number of daylily breeders in Abbeville with farms and they have a daylily festival every year.

Lisa has it right. Your trees are dropping leaves due to the leaf spot fungus. Nothing you can do now. You can do some preventative spray next year, but the fungal disease won't seriously harm your crepe myrtles. They just start to look funky in late summer, like a lot of other plants after 3 weeks of no rain and mid 90 temperatures.