I am not an expert by any means, but several years ago I cut back a huge confederate rose for a neighbor after it went dormant for the winter. I put the cuttings in a 5 gallon bucket in a cool bright room. I changed the water about once a week. I had lots of rooted cuttings in the spring. And his plant came back strong the following spring- just not as tall as before. The best time to prune is during winter dormancy.I'm sure those with more experience will chime in soon with better info.

Most new lateral stems come from between the leaf and the main stem. In zone 7 your limbs will die in winter but come back from the roots. I have waited until the new limbs get waist high (late spring or early summer) and then pinch out the tip. This causes the laterals to grow and your plant will get bushier.