Pruning Leggy Knock Out Roses for a Compact Shape

Knock Out roses that become tall and spindly with blooms only at the top are often reacting to excessive fertilizer. Too much nitrogen pushes out long, weak canes instead of a dense, bushy form. The solution is a hard rejuvenation prune: cut the entire bush down to about 18 inches in early spring. This encourages vigorous new growth from the base, creating a fuller plant.

Going forward, prune Knock Outs back by about one-third each spring to maintain shape. Fertilize sparingly—only in spring and midsummer—using a balanced rose food. Overfeeding is the primary cause of leggy growth in these otherwise low-maintenance shrubs.