How To Trim Knock Out Rose Trees


The Knock Out rose is a hybrid (Carefree Beauty and Razzle Dazzle) shrub rose that blooms 3-inch red roses from spring until frost. Rosarians love the Knock Out for its disease resistance and ability to self-clean (no deadheading is necessary). California Master Gardeners advise not to prune your Knock Out rose until after its second year, just prior to bloom, in late winter or early spring.

Step 1

Place the pruners into the plastic tub and pour enough Lysol over them to cover. Allow them to sit in the disinfectant for three minutes, remove and rinse under running water. Dry the pruners prior to using.

Step 2

Rake back any old mulch, leaves, dead flowers and other detritus from around the base of the shrub and dispose of it.

Step 3

Remove any dead flowers and wood and cut off any canes that aren't a healthy green color, but are black or mottled.

Step 4

Cut off all long branches that extend beyond the rest of the plant. Cut them, at a 45-degree angle, 1/4 inch above a bud.

Step 5

Prune the rest of the shrub into a round shape, 24 to 30 inches in height. You may have to stand back occasionally and make sure that it isn't lopsided.

Step 6

Fertilize after pruning with rose food at the rate suggested on the fertilizer package.

Step 7

Water the Knock Out rose until the water puddles. When it drains, add a 3-inch layer of fresh mulch to the soil around the shrub, keeping it 2 inches away from the bark.

Tips and Warnings

  • The Knock Out rose is patented, so it is illegal to propagate it without a license from the patent owner.

Things You'll Need

  • Sharp pruning shears
  • Lysol disinfectant
  • Rake
  • Rose food
  • Mulch


  • ‭"‬California Master Gardener Handbook";‭ ‬Dennis R.‭ ‬Pittenger‭; ‬2002
  • University of Arkansas: Plant of the Week, Knock Out Rose
  • University of California at Davis: Rose Pruning Facts
  • Raleigh News Observer: Pruning Knockout Roses
Keywords: prune Knockout roses, trim Knock Outs, Knock Out roses

About this Author

Victoria Hunter, a former broadcaster and real estate agent, has provided audio and written services to both small businesses and large corporations, worldwide. Hunter is a freelance writer specializing in the real estate industry. She devotes her spare time to her other passions: gardening and cooking. Hunter holds a Bachelor of Arts in English/creative writing.