I keep a bay tree in a pot. It is hardy in my area but I bring it indoors overwinter.
I prune it back in the fall and dry those leaves for use in cooking.
The bay should stay on the dry side through winter when its' growth has slowed.
I think when potted the roots will be vulnerable to freezing temperatures.
As a result, I would move it to a protected area when temperatures drop to freezing if you are unable to keep it indoors.
