I had one that was doing well. Ok it was lots of tiny ones tied together on a slab of wood. I took it off the wood and siliconed the pieces to a piece of umm that wood from the pet store that isn't grapewood.
Anyway, it got a little dry, so I added a little live sphagnum moss here and there and made sure they were getting light and some air. They were growing.
Unfortunately, after several rearranges of the tank, I ended up knocking them off the wood and into the substrate, one little piece at a time. I'll be getting some more soon, to try again.