First of all, I know nothing about roses. I saw beautiful full round knockout roses in the area so I bought planted about 10 bushes this spring. I cut them back just after planting because they were spindly looking. They grew fine throughout the summer, although they are still not really the shape I would like - I want more of a round big bush they are more tall thin at the bottom. It has grown cold in Nebraska and there have been mornings with frost on my car windshield. I really don't know what exactly to do with my bushes for winter, as everything I read on the internet just confuses me more. Can I cut them down now and, if so, how short can I cut them? If not now, when should I cut them back? Do I need to cover them for winter and, if so, what is the cheapest easiest way to do this? Any info you could provide would be helpful!!! Thanks!