I have had two clumps of Bletilla striata in partial shade come back for 2 & 3 years respectively in my home garden in semi shade. I have also lost plants from earlier attempts to grow them in the same general area. They are just emerging again now. I have mulched them, not heavily, couple of inches, for the last 2 years & we have had temps down to -15 to -20F in that time albeit with snow cover. Perhaps of more interest however is that I was just shown a clump at Cornell University in an experimental garden that is about 2 feet by 15" & this on top of a rise, in full sun & in full flower. It has to have been there for about 4-5 years minimum. While I am not sure, I doubt that the Cornell clump gets any mulching for winter. Perhaps plants vary in their hardiness, depending on their origin, but those in the Cornell clump certainly seem to be quite hardy in zone 5. Not sure about mine yet, perhaps in another 5 years? Robin Bell, Ithaca, New York.