One thing to keep in mind in this discussion is that in some plants roots are evidently less cold hardy than the upper parts of the plant. Conifers hardy in the ground well up into Canada sometimes die during our comparatively wimpy winters when grown in pots above ground. And I've had bulbs of Lilium regale, ordinarily a very hardy and reliable plant, die when grown in pots left above ground during the winter. I have no idea what the explanation for this is, but it does seem as if bulbs which freeze from the bottom up so-to-speak (i.e. where the roots freeze before the upper parts of the plant) are more likely to die. Ever since I learned that Nerine bowdenii is a reliable garden plant in northern England and coastal Scotland, in areas where they experience, at least temporarily, winter conditions comparable to those here in Maryland, I've been encouraged to try this plant again as a garden plant. For over twenty years it has been commonly and inexpensively offered in local shops in the spring: but I've never heard a local gardener crowing about his or her great nerines! Have they all died? Or do they start to bloom so late that the buds get frozen? Or do they persist but not flower? I don't know. Jim McKenney