Yeah, I've had mine survive a winter but the ones at the museum kicked it a couple of years ago. My butterfly pea is also supposed to only be good to zone 10 but it comes back from seed once the weather warms up. I like to stretch my zones and see what I can get away with. The Giant Milkweed are right next to the house and Mom likes to throw blankets on everything when it freezes which is probably why they've survived this long.
