There are two members of the walnut family that are worth a try in zone 3.
There are two members of the walnut family that are worth a try in zone 3. They are the butternut, Juglans cinerea, and the black walnut, Juglans nigra. They are both rare in Calgary. Iif you want to see them, they are in Stanley park, behind the tennis courts. Some thoughtful city employee had them planted and they are surviving.
The best chance for survival would be inner city, where a form of winter micro-climate exists. The walnut seems to be doing better than the butternut, but that may just be their seed source. Though rare, once established their beautiful long pinnate leaves will have you hooked.