I spotted a few at Home Depot last year in Cleveland and Chattanooga, so it might be something they will carry again this year. They were with the Pieris Japonicas, rhodos, etc. I was worried about it not over-wintering since most consider it hardy to zone 8 (and I didn't plant it till September), but it has since doubled in size and has no winter die-back. Looks great in a heavily shaded corner next to my fence. Hope you find one!

More recent literature I have read is now putting it at 7b. Seems very plausible to me...

We have one that has gone through two winters now. It gets droopy during a dip in the temps, like down in the teens and single digits and then perks right up. The freeze last spring burnt the new foliage on it, but besides that it has done great. I am hoping that it blooms for us this year.

Rebecca