Question
I live in Georgia and need to trim our knockout roses. Last year we trimmed them down to about 18 inches and they came back great.  We did have to trim in the summer because they were too high.  I used the electric trimmer and had no problem.  It is now almost January 2009 so when is the best time to trim them and will it hurt them to be cut back to 18 inches again?  Thanks.

Answer
Knock Out roses will do very well in your climate and will need to be pruned back or they will become a large bush. I would keep doing exactly what has worked for you last year. If you trimmed them in january and it worked, then by all means do it again. There really is no definite rules in gardening. Always do what gives you the best result. In regards to the hedge trimmer. I have found that if I go slower, the cuts heal up quicker as they are not as ragged as when I do it faster.