It did very well in its first year following spring planting. However, it froze to the ground during our relatively mild last winter and took a long time to recover. I mostly don't winter protect. I have to conclude it is no more than crown hardy in zone 5. I do believe it would do very well indeed in the warmer zones. The flowers are gorgeous and the foliage mostly disease free until late in the season when BS rampages throughout our area.