we pruned ours two weeks ago and all is/was fine. Those things grow like weeds, so I have never been worried about them.

You can prune roses anytime. I don't have knockouts, but I've heard you can just use a hedge trimmer on them. I'd wait for the latest bloom to end and then cut them to where you want them. Dont' worry, they will grow back and you'll get even more flowers. Most roses love being cut back and will put out more growth than before. You may want to add some fertilizer when you prune. Rose Tone is an excellent organic fertilizer that will encourage new blooms.

From my experience - you can trim them short, have them in a part shade, and they bloom with joy and reckless abandon! They are life savers for me.
And if you feed them - they would thank you with gorgeous blooms and beautiful healthy foliage.
~Natalie

I second buford's suggestion of Rose Tone, this is a must for rose growers/

If anyone is pruning their Knockout roses, I would love to have the cuttings for trade. Check out my list. Thanks in advance.

All of the Knock Out® Roses are patented. Asexual Propagation is prohibited without permission from the Conard-Pyle Co.