It could be due to too much fertilizer, but only if you applied a lot more since planting them in the spring. It may be due to a lack of water. However crapes tend to get that look at the end of a long hot summer with the effects of drought, heat, pests like aphids, etc. They should come out again in spring with new fresh foliage that is healthy. It is too late in the season now to try and fix anything other than to insure the soil is moist but not soggy wet. You don't want to promote new growth this late in the season.
Thanks for the question. Please stop in again soon!
Q&A Library Searching Tips