Knock Out Ros Facts


The Knock Out rose is a cultivar that grows as a shrub. It is drought-resistant, easy to grow and hardy to USDA zone 4. Knock Out blooms provide a burst of red in a compact 3-by-3-foot form.


Knock Out roses were created by William Radler, a Wisconsin rose breeder and director of the Boerner Botanical Gardens. In 1988, he cross-bred Carefree Beauty and Razzle Dazzle. In 1992, he began testing the cross-breed.


In 2000, the Knock Out rose won the All-American Rose Award. In the cultivar's first year on the market, more than 250,000 were sold. It went on to become the fastest-selling rose in history.


Knock Out roses are fire-engine red in cooler weather and cherry red in the summer. The leaves are purplish-green, turning to a burgundy hue in the fall. It has terminal clusters of flowers, each of which are 3 inches wide.


The Knock Out rose grows best in full sun or light shade. The soil should be fertile and well-drained. Water and fertilizer should be applied throughout the growing season for continuous blooms.


Prune your Knock Out roses in spring before new growth appears. Prune them again during the growing season when you need to control the size of the shrub.


  • Botany Shop Garden Center
  • University of Arkansas Division of Agriculture
Keywords: shrub roses, Knock Out roses, cross bred roses

About this Author

T.M. Samuels has been a freelance writer since 1993. She has published works in "Arthritis Today," "Alabama Living" and "Mature Years," and is the author of a gardening book. Samuels studied pre-medicine at Berry College.