Knock Out series lives up to its name

Allen D. Owings, Young, John, Gill, Daniel J.  |  9/26/2008 6:33:31 PM

Knock Out is a shrub rose that fits perfectly into a sustainable, low-maintenance landscape. (Click to download. Photo by John Wozniak.)

News You Can Use -- Sustainable Landscapes, Distributed 09/26/08

By LSU AgCenter Horticulturists

One of the most exciting new plants for home gardeners released in the past few years has been the Knock Out rose. It is receiving a lot of attention, and rightfully so. More than 6 million plants are being sold every year across the country. This rose fits perfectly into a sustainable, low-maintenance landscape.

Knock Out is classified as a landscape shrub rose. This type of rose does not make a great cut flower, but it gives your landscape an abundance of flowers for 75 percent of the year. It blooms practically nonstop during the growing season from March to November in South Louisiana and April through October in North Louisiana. In warm winters, it has flowers in December, January and February. Blooms are a fluorescent cherry red, with a single petal complemented by glossy, burgundy-green foliage.

Knock Out has been praised for outstanding black spot disease resistance. At the LSU AgCenter’s Burden Center in Baton Rouge, this variety has received the best disease-resistance ratings since it was first planted in center’s All America Rose Selections display garden in 1999. Knock Out roses are less prone to black spot disease than traditional hybrid tea, floribunda and grandiflora roses, which makes them black spot resistant. Sometimes they are promoted as black spot immune, but they are not.

Knock Out roses do not need to be sprayed with fungicides, making them a highly sustainable landscape plant. They also do not need to be “deadheaded,” which makes them virtually carefree.

Plant these roses where you would plant other roses. They need full sun, minimum irrigation and well-prepared, well-drained landscape beds. They prefer a soil pH between 6.0 and 6.5. Although most of us plant roses in late winter through the spring, fall is a great time to add new roses to your home landscape.

Knock Out is an AARS winner from 2000, but it took a couple years for the variety to be on the market before most horticulturists realized how great a plant it is. Although it is advertised to grow to a height of 4-5 feet with a spread of 4-5 feet, it can easily reach 8 feet tall if not pruned.

The newest Knock Out roses being featured at the LaHouse Home and Landscape Resource Center on the LSU campus are Double Knock Out and Pink Double Knock Out. Double Knock Out was introduced in 2006 and has a double flower form with the original cherry-red flower. Double Pink Knock Out was introduced to the gardening public in the fall of 2007 and has double, medium pink flowers.

Other Knock Out roses include Pink, Blushing and Rainbow. Watch for the release of Sunny Knock Out (yellow blooms) in 2009.

Try Knock Out roses in your home landscape. You will be amazed with the bloom and easy care for these great rose varieties.

Visit LaHouse to see how the Knock Out roses are performing. The center is open to the public.

LaHouse is located near the intersection of Burbank Drive and Nicholson Drive (La. Highway 30) in Baton Rouge across the street from the new LSU baseball stadium and next to the LSU golf course parking lot. Go to and for more information.


Contacts: Dan Gill at (225) 578-2222 or
Allen D. Owings at (985) 543-4125 or
John Young at (225) 578-2415 or 578-2222 or
Editor: Mark Claesgens at (225) 578-2939 or

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