I have a mature crepe myrtle tree. It does great for a while in the early spring with new foliage, but then the leaves turn brown and yellowish and it looks sick for the rest of the summer. It has very few, if any, blooms. We live in Florida and we have a sprinkler system. This has been going on for about the past 3 years. Any ideas?
Certified GKH Gardening Expert
This sounds like it could be a fungus. It would go dormant in the cooler months but come back strong in the warmer, wetter months. I would recommend treating the trees with a fungicide. I personally like neem oil (sometimes sold as fruit tree oil - check the label), as it will treat both fungus and pests, so it is a double wammy. Here is more information on it: https://www.gardeningknowhow.com/problems/pests/neem-oil-uses.htm