I have a passion flower vine, still in its nursery pot. I was told to leave it in this pot until next spring, prune it back, and then put it under the house to overwinter. I am unsure of the type. It has a dark purple flower. I am in zone 7. Is this the best advice? Should I dig a hole and put it, pot and all in the hole and then mulch? I would prefer not to bring it inside, but could if that is the only option. Please help. Thanks.