Winter hardiness for Ixiolirion here in Maryland is not an issue. My experience suggests that like Allium caeruleum, it's easy to grow but needs dry summers. Because the Ixiolirion and the Allium are very inexpensive as bulbs go, most growers don't take their culture too seriously. They are both readily available, and have been so for decades. You would think local gardens would be stuffed with them by now. I'm convinced that both require dry summer conditions here. I've grown Allium caeruleum and Ixiolirion off and on for decades. Until I protected the Allium with a glass cover during the summer, it rarely reappeared or prospered or bloomed after the first year. Now that I cover it during the summer, it increases prodigiously and blooms very freely yearly. I'm not currently growing the Ixiolirion, but it's on the list of plants for my "summer dry beds". I'm going to try some of the small eastern Asian lilies such as Lilium cernuum, L. pumilum and L. concolor under these conditions, too. Jim McKenney Montgomery County, Maryland, USA, USDA zone 7, where the weather has done a flip flop; it's coolish and wet today, nothing like the nearly suffocating steam bath earlier this week.