Knockout rose bushes are identifiable by their flower petals that bend outward instead of forward like most rose varieties. The center of the flower has a visible yellow or white section, unlike other roses. Because the Knockout rose bush is a hardy variety of plant, it can quickly grow out of control. Regularly pruning Knockout rose bushes will help control the plant's size and increase the number of roses the bush produces.
Wait until late winter or very early spring to prune the Knockout rose bush, before it starts to regrow.
Examine the rose bush for any limbs that do not have any flower buds, that appear broken or diseased, or that are a darker color than the surrounding stems. Cut off these dead stems with pruning shears 1/2 inch from the base of the bush.
Locate two or three of the tallest and oldest stems near the center of the bush and prune them off 1 inch from the base of the bush using pruning shears. This opens up the bush and encourages new foliage to grow.
Cut off 1/3 of each plant stem using the pruning shears to improve the plant's shape and promote additional blooms. Look for a small bud on the stem that is facing away from the bush and cut the stem just above the bud angled towards the rose bush.