Have you grown these in pots and overwintered them inside? I know they grow well in zones south of OKC, and I'm trying to overwinter one in the ground in a micro climate area outside and letting one go dormant inside in the garage. Don't know if either will live.
I've not grown them personally but see them as a good option for a northern tropical garden. So long as the ground does not freeze in your micro climate area, you may get lucky. Good for you, too, that you have a backup inside in the garage!