Josie- yes it definitely freezes. We have TERRIBLE freeze-thaw cycles here...20 degrees one day 70 the next...I observed them some more last night and from what i can see I would suggest this- if you are going to plant in the boggy/wet areas try to have them be dormants ( as they handled the wet MUCH better than the EVs) AND if possible only send the clumps down there...anything with a split crown is much more succeptible to rot in my experience...most of the ones i lost were single fans
PS- yes i did have to plant all 300+ myself...LOL it took all summer and many sore knees and hands!
