Brad I allow my J. multifida to go pretty much dormant during the winter. I cut back almost completely on watering. The foliage drops but it begins leafing out and blooming almost immediately after I resume watering in the spring. Actually it sends out flowers before the foliage. It is sensitive to cold, especially when it's small. I have a larger one that withstood a freeze when the greenhouse lost power but a small plant died.
