The problem with that exposure is that anything evergreen would be subject to severe sun scald (particularly if there is snow cover) and wind dessication during winter - even for in-ground plants facing that direction, in your area. Additionally, a good rule of thumb is to look for plants hardy to 1 - 2 zones lower than you are for container-growing, so that limits the possibilities further. However it doesn't hurt (except the wallet) to try!

An oft-recommended tree is the Alberta Spruce, which would be hardy enough. Problem is that you have to stay on top of them for spider mite problems, as they are quick to brown out.

Some other possibilities would be an upright taxus spp (yew) or aborvitae like Thuja occidentalis ÂFastigiataÂ. In any of the cases, you want to make sure that you have them in sturdy heavy pots that have good drainage and won't tip over in strong winds or with heavy snow bending an upright tree down.

Is there wind in the summer too? Maybe you could do something just for shade in the summer that dies back or dies off in the winter? Perhaps a vine on a trellis? Or cannas if you can water them a lot in the heat.

OK, so now I would like suggestions for the fastest growing, nastiest, most tenacious vine that will prosper in heat, cold, snow and wind. Doesn't have to be pretty. I am about ready to go dig up some sumac and stick that in a planter since it grows anywhere and comes back each year. Can anyone think of a vine that will do as well as sumac? Thanks.
Mudlady

Maybe virginia creeper?