How do I prune knockout roses? What is the correct time of year to do this?
prune in june
You really do not have to but you can do a shaping pruning anytime. Here is a link to an article on this subject for you too: https://www.gardeningknowhow.com/ornamental/flowers/knockout-roses/prune-knockout-roses.htm and https://www.gardeningknowhow.com/ornamental/flowers/knockout-roses/care-knockout-roses.htm