Q: How low can I prune a Knockout rose?
A: Much depends on how high you want them to be in summer. I like mine 36 inches tall, so I prune to 18 inches in January or February. They will grow to five feet tall if left unpruned but they look a bit open and ragged for my taste at that size.
Cut out any dead branches first, then any that cross through the middle. Finally, reduce the height of the rose to half the height you’d like it to be in summer.
