That's not very encouraging, I've got about a dozen of them I was going to try to overwinter. I'll have to dig them out of the 20" planters, probably have to do some root pruning and put them in 12" planters so I can move them down and back up the stairs in spring. I thought just let them go dormant from the cold but before the soil mix freezes, do some top pruning as well and just enough water through winter to keep them alive. I'll have to do more reading up about it and see if what I'm planning will even work.
