I've never tried it with cuttings but have used it to propagate mango seeds, as well as to house seeds in for cold stratification.

I've tried crepe myrtles several times from cuttings but haven't had any luck getting them to live. I've tried with and with out rooting hormone, with and with out a humidity chamber, and even with a bubbler. Only thing I haven't tried is an automatic misting system with bottom heat and of course, sphagnum moss. So, if using moss does the trick, let me know, because I sure would like to root some!

I have read that you can actually air layer these pretty easily though. Need to try that one day.

I have tried equal parts of Sphagnum moss, coarse sand, and perlite for crape myrtles and was able to start about 6 of them early spring. They were 3" cuttings under moist conditions, and now they are 6" long and already flowered. Hopefully they make it through their first winter, but our winters are pretty mild with only a couple of frosts a year.

Elly