Oh, I like Chelsea too! The one I had difficulty with was a rooted cutting of hoya kerrii. The cutting was rather large, with 4 leaves, and it did root, but started developing a black mold underneath the leaves. I think it was too humid and not enough air circulation at the time, which has been corrected.
I've seen the kerrii parent plant at the nursery and was tempted to buy it- any experience with the sweetheart hoya?
