Knock Out Roses – Low Maintenance Beauties

The Knock Out Rose variety was developed by rose breeder William Radler. A prolific rose gardener well- versed in the demands of his large, sprawling rose gardens, Mr. Radler’s objective was to “breed the maintenance out of roses so I wouldn’t have to cut back as the years passed.”

Mr. Radler concentrated on improving cold tolerance (so northern growers could cut down on plant loss and cold protection chores in northern zones), and disease resistance (to reduce the need for weekly spraying and pesticide use).

The result of his endeavors is the Knock Out line of shrub roses.

Knock Out Rose Characteristics

Presently there are seven varieties of Knock Outs, beginning with the red single Knock Out (the first one developed). All are shrub roses that grow from 3′ to 4′ high, with a 3′ to 4′ spread. They are disease and pest resistant (including black spot), drought tolerant, and cold hardy to around Zone 5.

They’re also repeat bloomers, with a fresh bloom cycle every 5 to 6 weeks, from spring to first frost. And they’re considered self-cleaners, so dead-heading is not an issue. Presently, only one of the seven Knock Out varieties is fragrant (Sunny Knock Out).

Care is easy. In early spring, cut the plant back to about 12″ to 14″ above the ground to promote prolific flower production for the coming season.

Where to Use Shrub Roses

Knock Out roses are perfect for new gardeners. They work great in borders or mixed beds along with other shrubs, like long-blooming Encore Azaleas. Add drifts of perennials for color contrasts throughout the season.

Knock Outs are also good as mass plantings, to anchor a foundation, or as under plantings to balance small ornamental trees like Crepe Myrtles. Grouped in odd numbers of threes and fives, they make great color statements against picket fences. A single Knock Out rose, strategically placed to contrast against evergreen background shrubs, makes a fine accent.

The ease of caring for Knock Out rose varieties have resulted in an abundance of these roses appearing in home and commercial landscapes. They’re readily available, and may be over-stocked in box store outlets. Rose elitists deplore the over-reliance on Knock Out roses by gardeners and landscapers, but the truth is these shrub roses are easy to take care of and prolific bloomers, and pretty to boot – perfect requirements for the time-stressed homeowner with more on his plate than caring for roses.

Planting Knock Out Roses

• Dig a hole twice as big as the container. Mix peat moss or manure in with the native soil.
• Water the rose well, then remove from container (if planting bare-root stock, soak roots in a tub for a few hours before planting).
• If any canes are damaged, now’s the time to prune them off.
• Loosen the roots, and place the rose in the hole with the bulb union 1″ higher than the ground surface (in Zones 6-10). In Zone 5, bury bulb union 1″ under the soil.
• Fill the planting hole and thoroughly water, adding soil and water as the plant settles.
• Mulch well with ground hardwood or pine straw.

Knock Out Roses Survive Harsh Environments

Knock Out roses are extremely tolerant of neglect – perfect for the inexperienced gardener or for use in new developments. In one condominium project in Georgia, developers bought over 80 Knock Out roses in containers. The plants were stockpiled and pretty much ignored through one of the hottest, driest summers on record and, on inspection by the project landscape architect, appeared to be dead. Most leaves were either gone or dried out, flowers were non-existent, and the soil in the containers was so dry it had cracked like a mud flat.

In an attempt to save what they could, developers moved the containers to a shaded, sheltered spot and commenced a regular watering program. To most everyone’s surprise, the Knock Out roses came back strong, leafing out and flowering as if nothing had happened. Most of the plants survived and were planted.

Knock Out Rose Varieties

There are seven varieties of Knock Out roses in various flower shades.

• Single Knock Out (Rosa ‘Radrazz’) – the old stand-by, in cherry red blooms.
• Double Knock Out (Rosa ‘Radtko’) – vivid red double flower form
• Pink Knock Out (Rosa ‘Radcon’) – bright pink single-petaled
• Pink Double Knock Out (Rosa ‘Radtkopink’) – double flowered hot pink
• Rainbow Knock Out (Rosa ‘Radcor’) – unique, yellow centered with coral pink blooms
• Blushing Knock Out (Rosa ‘‘Radyod’) – delicate blushing pink
• Sunny Knock Out (Rosa ‘Radsunny’) – bright yellow fading to cream. Fragrant!

If all-season beauty and easy-care are requirements, then Knock Out roses should be present as plants of choice on all gardener’s plant palettes.

Sources:

The Conard-Pyle Co. website, articles entitled –

• “William Radler, Rose Breeder”
• “How to Plant a Knock Out Rose”