Question
I have fairly big knock out rose buses. How far do I cut them back for winter? when is the best time, and what is the best spot to trim to? Also, can I use hedge trimmers since pruning shears would take forever?
  Thank you

Answer
As I don't know where you garden, the time to cut back your roses will depend on how nasty a winter you get. I would cut your roses back when they drop all their leaves off as pruning a rose sometimes activate it into making new growth and you want the rose to go dormant for the winter. Just cut back about 18 inches and that will leave some cane length if you do get some dieback on the rose bush. Sure go ahead and use the hedge trimmers I have and it works very well. The secret is to brace your legs and hold the trimmers steady and slowly make a pass across  the rose bush. Going too fast makes the canes really messy and can cause problems. If you use a hedge trimmer, it doesn't matter then where you cut just go straight across at aound 18 inches.