I've had one in a pot for years. I leave it in a sheltered spot for winter, more for the sake of the pot. The plant is quite hardy here in south Wales.

Apparently it is hardy in zone 3 - 9

I had it in the ground for several years until our really bad winters of 10/11 11/12. so protect the pot and it should come through ok.

This is a good question for or member Bathgate - he gardens in New York and knows all about winters there.