Nobody seems to be able to answer your question. Have you tried the Vine Forum? Or maybe by googling it you would find what you want to know.

Guess this isn't something folks grow much. Thanks for your comment, blueheron. I did look on-line but most everything was about the other type. I did cut a couple stems that had bloomed. They have a milky exudate, so I suspect they'd need a little treatment. There was some wilting, but when they perked up, the blooms lasted for a few days. Kind of tiny, tho, and might not make much show.