Unfortunately, in your area, most of the very large clumpers wouldn't survive your Winters. There are some bambusas that might survive in your area, but would get a lot of freeze damage.

However, you need to look into the Fargesias and Chusqueas, the later being the taller and probably most hardy in your area.

Kt

Thanks a bunch, from the information I was able to get from different online retailers I was afraid that was going to be the answer.

How difficult would it be to keep one of the cold hardy runners in a 7'x7' area?
My fear is that by the time it got established the larger culms would be outside that area.

In your area, at least compared to here, the runners wouldn't spread that fast.

You could either install a barrier, or do some rhizome trimming twice a year, which doesn't take long, and will keep the grove in the confined area. However, a 7' X 7' area is not a lot of space for a runner to reach large size. They need a lot of room to get large.

I am not real familiar with the Chusqueas, but they can tolerate the cold, but not the heat down here. When temps get into the 90's(and over 100F), they tend to die back, but some can tolerate 0F so you need to look into them. Some get well over 20 feet in height. I think you will find one suitable for your area. If I come across any that I think will do well for you, I'll post them.

Good Luck

Kt