I'm sure preventing the freeze/thaw is important for the artichokes; we generally have plenty of snow cover here, which should help in that respect. There are a couple of spots next to the foundation of our house where I think I could get rosemary to overwinter, although I've never tried it, I always grow it in planters; maybe I'll stick a few of the (rosemary) plants in the ground there and see how they do - if that works, the artichokes might make a nice "foundation planting," they're certainly large enough!
