As a zone 2-3 plant, it will likely over-winter w/o temperature protection in your zone. You'll need to add some snow on top of the soil (or water) every now & then to prevent the soil from drying completely. They are quite susceptible to winter burn in containers if you're not careful about siting. It's best to keep them shaded & out of wind. If you have a place to simply bury the container where it's shaded & out of wind, preferably against the foundation of a heated building, you can bury, mulch, & forget until spring. A product called Wilt-Pruf is fairly effective at preventing winter burn, but you'll likely need to apply two or three times for it to work best. Wrapping foliage in burlap is also very effective at preventing burn.

Al

Thanks Al,

The soil here is quite sandy and easy digging so I'll probably buried it between the house and a hedge, and mulch it and leave it til spring.
Lil