Knock out roses are hybrid rose bushes designed to be more cold hardy and easier to care for than other rose varieties. They also produce a set of blooms every five to six weeks from late spring until the first hard frost. Since they are easier to care for, knock out roses actually don't need their faded flowers cut off to encourage more blooms, which is called deadheading. Rather, they drop their own flowers when they fade. However, to maintain an even cleaner look, you can still deadhead knock out roses like you would other roses, if desired.
Watch for wilted flowers. When they begin to fade and wilt, that's when knock out roses can be deadheaded.
Cut them off just beneath the wilted flower with a pair of hand clippers.
Discard the clippings, rather than letting them fall to the ground, to keep your rose bed tidy.