Wow so beautiful, I love them & would buy loads if I could only be sure which are really, truly hardy, rather than wasting my money on more that aren't! I bought an enormous pot of them from Trebah gardens one year but lost them the second winter.
Carol Klein on GW said a while ago that one type were totally hardy & one type not. When I'm faced with gorgeous pots of them in the garden centre that give very little information I never know if they are or not.
I got a lovely surpise this year when a tiny one appeared in a pot that I planted with it & lily bulbs years ago. It's never reappeared & then suddenly well over 5 years later it pops up & has one flower on! I shall ignore it & hope it thrives!