If our winters in the future are like this year was, above freezing almost all the time, I bet only a little styrofoam for just in case could save it. Or if it's the kind that survives indoors all the time then I perhaps can manage to keep it alive. :)

Did some digging and what do you know, drosanthemum has a common name in Finnish, jääruoho = icegrass. I wonder if it's an omen of what it can tolerate.