Early Spring, eh? Good to know. I'm glad somebody asked this. I happen to have just acquired a few new bare root specimens as a result of looking at Perennial Obsession's web site too late at night and while sipping a vodka and lemon.
I didn't want to put them into the garden going right into the rainy season, which BTW appears to be beginning right this moment, at my house anyway. So I potted them up and tucked them into my cold frame which I generally only use in the spring. It will be 5-10 degrees warmer in there and more to the point sheltered from rain. I figure they'll stay in there 'til April or May, and probably won't want to come out.