Moose - I have 4 Stewartii in the ground. Yes, they are cold tolerant, but not drought tolerant. The one in the front of the house, the gets the least water and the most sun, always looks like crap. The three in half shade in the middle of the garden, right near a knocker head, grow great. One of the largest ones is starting to block a pathway and I was going to trim it. I'll tie it back and take cuttings in mid-March.