"Ray" writes:

I have rooted a cutting from a golden bark willow, and it's thriving
in a small pot out in the yard. It's still a little too small to put
in the ground.

But winter is coming, and I don’t know whether I should leave the
cutting outside in its pot, or bring it inside.

I guess the question is whether it needs a period of dormancy.

I think the real question is can a tree be too small to survive the
winter.

I don't think so.

Lots of tree seedlings survive winters in my experience.

--
Dan Espen