I have to confess...I have a few of these in a raised garden here in upstate NY (zone 5b, with consistent snow cover) and they've survived there for many years. "Survive", however, is the best they do - maybe one or two blossoms now and then. They assuredly do not thrive. This discussion reminds me that I may have a couple of bags of seeds sitting around, one of mixed forms and the other of silver-leaved plants with green edges (descended from a beautiful plant John Grimshaw gave me, long ago). I will see if I can find them, and if I do I'll send them to the seed ex. Thanks in advance for not writing to make private arrangements - Ellen