Not sure, a buddy of mine wanted to market them on ebay if we can root them, the guy who gave it to me, I can't find anymore, it's been over 10 years ago online, where he lived it was warm, NM. He never tested it against the real cold, we had snow in my part of town last year in the last week of April I have never left the mother tree without any wood chips at the base and a tarp over it, if I can make some clones I will leave it totally unprotected, and even take pics in the snow. I was hoping last year for that, but I had bad luck rooting I even had a large plastic bottle around one branch which I remove and have it potted in the garage, with my black jacks but I even doubt it rooted much. I would have to say looking at a 3/4 inch cutting the bark is thicker than a Chicago hardy bark, which roots like a weed for me, but not this one she's hardy, and very hard to clone. Which, if I figure a way to do it, i would be very happy