How to Maintain Knock Out Roses


Every flower has its fan club but the rose is welcome in any garden. From the rugged rugosa to the refined hybrid teas of the last century, each rose has its place. The Knock Out roses originated by Wisconsin rosarian William Radler may be the easiest to maintain. Radler's rose, marketed by the Conad & Pyle Co., is hardy through most of the U.S. and blooms throughout the summer. Its undemanding habit and disease resistance have made it one of today's most popular landscape roses.

Step 1

Let Knock Outs establish themselves their first season. Water them so they get an inch of water a week (including rain) and cut flowers as desired. Mulch their roots with a summer mulch of equal parts soil and compost, leaves, manure or peat moss. Don't fertilize until the first blossoms appear.

Step 2

Remove summer mulch in the fall and put the same depth on for winter after the ground has frozen. In areas with severe winters, mound Knock Outs; pile mulch and soil a third of the way up the plant in December after the rodents have found other places to overwinter.

Step 3

Fertilize Knock Outs with regular slow-release rose food according to the directions on the package. Fertilize as the first blooms appear; the shrubs will bloom for five to six weeks, then rest before a second period of bloom.

Step 4

Cut flowers for your home but, beyond some trimming to keep them shapely, Knock Out roses require no special pruning or deadheading. Removing spent blooms does, however, encourage a denser bloom.

Step 5

Keep a Knock Out rose tidy by shearing it to one-half to one-third of its height after the last hard frost in the spring. Remove dead wood in late winter or early spring. Rejuvenate your Knock Out rose periodically when it becomes leggy or bloom becomes thin. Cut the canes back to a foot to 18 inches high in early spring.

Tips and Warnings

  • Although these roses are remarkable, they still need at least eight hours of sun a day to bloom well. Plant them in a sunny, open place in your yard and allow plenty of space between them. They will easily grow to 4 feet tall and 4 feet wide. Mulch the roots---not the rose bush. Keep mulch a few inches away from the main stem to keep plant tissues in open air. Like any rose, Knock Outs will develop fungal infections if stifled by poor air circulation.

Things You'll Need

  • Hand pruning shears
  • Loppers or hedge shears
  • Garden spade
  • Summer and winter mulch materials
  • Water and bleach or rubbing alcohol


  • The Knock Out Family of Roses
  • William J. Radler

Who Can Help

  • Care of Knock Out Roses
  • Knock Out Care
Keywords: Knock Out roses, maintaining roses, rose garden

About this Author

Chicago native Laura Reynolds has been writing for 40 years. She attended American University (D.C.), Northern Illinois University and University of Illinois Chicago and has a B.S. in communications (theater). Originally a secondary school communications and history teacher, she's written one book and edited several others. She has 30 years of experience as a local official, including service as a municipal judge.