Question

I live in Chattanooga, TN.  My knockout rose bush is about 4 ft tall and covered with roses (Oct 12).  I would like it to be about 2-3 ft tall.  When do I prune?  Thanks!

Answer
The basic rule in your area if you want a smaller bush, is to just trim it up for the winter, leaving some growth in case it does get some die back during the winter. However in your area, you don't get really cold winters but I would still cut the bush back to about 3 feet. Then in the spring, when it starts to leaf out, prune it back hard to 18 inches. Then it will grow back to a smaller bush. Don't forget that you can also cut a rose back in the summer. So if your rose throws out a long cane or canes, simply cut it back even with the others. Keeping it down to 2 or 3 feet may be difficult as this rose likes to grow in warmer climates. I would pull back on the fertilizing and only give it some when it starts to grow in the spring and then in about the middle of the summer. This will keep the bush at a smaller size for you.