Q.green moldy looking bark on crape myrtles
We live in NJ and waiting for crape myrtles to bloom, planted about 5 years ago, about 8 feet tall. Noticed bark is shedding, but bark looks moldy green. I found your very interesting article about how they will shed their bark, but the moldy look has me concerned. And it looks like the tips of the trees are yellowing, as if dying. Would appreciate any advice. Thank you. Great website!
What you are describing sounds like either moss or lichen. Both are harmless to the tree, though tend to affect trees that are stressed, which sounds like your may be with the yellowing leaves. Here is more information:
https://www.gardeningknowhow.com/houseplants/epiphytes/treatment-tree-lichen.htm
https://www.gardeningknowhow.com/plant-problems/weeds/moss-on-plants.htm