I've been overwintering Ledebouria cooperi in my unheated breezeway here in Zone 6 for years, leaving it in the pot it grows in. A few years ago, it had multiplied enough that I experimented with putting some bulbs in the ground. This is the third spring in a row it has returned. I don't know that I'd claim it's thriving out there, but it has definitely survived the cold. I find it to be pretty vigorous in a shallow pot. Vivien Bouffard Norwood, MA Z6