I'm not sure Karen? Our growing season isn't long enough sadly and I have to rely on mild winters to preserve as much of the stem as possible. I sometimes pile mulch around them but I don't cut them back until late winter, but it's a nasty mess when I do lol. I may cut them to a foot or two before they turn mushy and pile some leaves around them for protection. For the most part I rarely protect them, but they still come back.
