My store bought rose stems are growing? Please help me keep these babies alive!

I have had these for about 2 weeks in water and obviously have the will to stay alive. How do I properly keep them going and not kill them? I’ve tried keeping growing stems alive before and failed (mostly because I forgot about them), but now I’m prepared for the responsibility. Would putting the cuttings in moist vermiculite work?

I live in Florida and there’s no sign of weather getting cold again so I’m not worried about cold killing them, but I do worry about the eventual scorching heat that is about to plague us.