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What Is a Knockout Rose?

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The Knock Out rose is a shrub that produces vibrant roses in three primary colors: pink, red and yellow. Due to its low maintenance requirements and overall hardiness, the Knock Out rose allows even the most inexperienced gardener to add roses to their landscape.


Rose breeder, William Radler, has a fascination with roses that began in early childhood. At age 9, he began planting and caring for his own roses, and learned to propagate his own plants. He soon realized that roses required a lot of care in order to grow perfectly, and people without a lot of time to devote to the care of roses, cut back on their rose gardens. He then began a life-long pursuit to create a hardy rose that required little maintenance and ultimately bred the Knock Out rose.


The Knock Out rose family includes seven different varieties: the Knock Out rose, the Double Knock Out rose, the Pink Knock Out rose, the Pink Double Knock Out rose, the Rainbow Knock Out rose, the Blushing Knock Out rose and the Sunny Knock Out rose.


The Knock Out rose was specifically bred to be disease resistant, eliminating the need for pesticides, thus improving the environmental quality of the shrubs. Beginning in the spring, Knock Out roses bloom every five to six weeks until a hard frost. Knock Out roses are considered “self-cleaning” roses in that the shrub will automatically release dead flowers, eliminating the need for deadheading.


Knock Out roses can tolerate winter temperatures through Zone 5, which represents an average annual minimum temperature of 10 to 15 degrees below zero degrees Fahrenheit. The plant may need protection during the winter in the coldest regions. Knock Out roses can tolerate even the hottest areas of the United States, making them an ideal plant for southern states and desert areas.


You can prune Knock Out roses in early spring to control the size of the shrub. Without any pruning, the shrubs can grow up to four feet wide and tall, making them a beautiful option for creating a border hedge. If you wish to maintain the shrub at a smaller size, use hedge trimmers to shear the shrub to a third or half its current size, leaving a minimum of 12 to 18 inches of shrub above-ground.

Expert Insight

After its introduction in 2000, the Knock Out rose received the prestigious All-American Rose Selections award for outstanding garden performance and garners the most sales of any rose in North America.

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