I think that I'm on the edge of their range in Rochester, NY. There's several left of the ten I planted that keep experiencing winter kill and resprouting from the roots, but most of them have given up the ghost. They looked great their first year from bare root plantings in the spring. And since the past two winters have been mild, I don't expect that they'll do any better in the future. Seeds from local hybrids have taken off though and are doing great in their second year. Nice job on your success!