Mine has been at the northeast corner of a ground level deck for at least 14 years, and is about the same size as yours, although very full. I have to prune off broken canes every spring, as it gets a lot of snow piled on it. Not too much bs -but is is a very well ventilated, even breezy location.
I have had great luck pegging canes down in the spring, and separating off new plants in the fall or the following spring to give away.
I really love this rose, as she takes absolutely no special attention other than the spring pruning.

Thats great to here. I had very little blackspot with her until the rugosa started invading her space. I'm hoping a more open spot will help with this problem.

Mark