I've never heard of dregea, so I looked it up and found that it's a very tender tropical vine in the milkweed family. I've been posting on this forum for ?10 years or more, and I can't remember anybody mentioning it. There are a few people in south Florida who post here occasionally who could probably grow it successfully, but the rest of us, if we want a milkweed vine, go with something hardier like Cynanchum laeve/honeyvine.

Sherry