BBE - almost all Hoya leaves will root, but whether they grow or not is another story altogether. It's my understanding that some of the stem tissue has to be present in order for the leaf to produce new growth. There's really no way for you to know if you've gotten some of that tissue or not without simply rooting the leaf and then waiting. I have always made it a habit to root healthy leaves, but I have to admit that in the 30 some years I've been doing this, only one (recently, in fact) produced new growth. It took about 2 months for new growth to emerge. So my answer would be root the leaves (as you are doing it sounds fine) and just wait and see. Once the leaves are abviously rooted, just set them in a nice warm, sunny location and hope for the best.

Denise in Omaha

There have been several forum members who have shown that a single rooted leaf can develop new growth but that is always the exception to the rule. As an experiment I rooted a single Hoya acuta leaf with about 2"-3" of stem and it has been many months with no new growth. Although it is possible this is a very slow method of propagation. I always push any leaves I break off back into the pot to help fill it out, they always root but no growth as of yet.

Mike

Thank you for the comments, I guess time will tell, till then I will remain optomistic.