Need ideas for starting cuttings from my star producing Japanese persimmon and strawberry guava...

I've tried a couple times this summer with no luck. They are heavy with fruit now. I cut a likely twig... Strip an cut leaves down, to about 6-7"of twig, root hormone, put in store bought potting mix. Keep moist an shaded. They hang out for a month or so then rot.... . What am I doing wrong? It has been hotter than average here... And is this a spring only venture..? Maybe the potting mix contaminated..? Maybe my thumb is brown this summer....? Heh! Ideas welcome! The mature plants have been the most awesome producing plants for over 10 years now and I'd love to clone them...

Annie,  the best method of propagation for those plants is Air-Layering. I posted the procedure here, Air Layering late season

Strawberry guava will take under mist after 2-3 months, generally. Maybe a 50% strike rate.

Persimmon does not want to root with cuttings at all. Plant American persimmon seeds, then graft scion wood on top just before they break dormancy in the spring. You'll have good luck. Don't be scared - just graft!

You can also grow Japanese persimmon from seeds. They'll make good fruit, but it's not exactly true to type.