I doubt it. I'm on the cold side of Z6 and Santa Rosa often suffers cambium damage here. I believe it may have more to do with spring fluctuations than winter cold, however. I've seen the worst damage in the last 3 years when winters have been pretty mild. Shiro and Methely are much tougher in my nursery and the orchards I manage and bear more consistantly by far. Unfortunately to most they don't taste as good. Right now I rate Fortune as the most promising really tastey Jap plum here. Haven't had any cambium damage on trees right next to damaged Santa Rosas and killed Elephant Hearts.
[NAFEX] Santa Rosa in zone 3?,
Alan Haigh, 06/16/2008