How to Grow Knock Out Roses
By: Julie Day
Knock Out roses are the epitome of low-maintenance.
Forget what you thought you knew about growing roses! Here’s a family of roses that leaves fussy rose gardeners twiddling their thumbs with no work to do. If you like low-maintenance gardening that packs a wallop, the Knock Out® family of roses are a must have for your yard or garden. Here’s what you need to know about growing Knock Out roses.
Knock Out roses can tolerate partial shade.
About Knock Out Roses
You’ve probably seen these roses, whether or not you knew it. Since being selected as an AARS (All-America Rose Selections) winner in 2000, the patented Knock Out roses quickly became the largest-selling rose variety in North America. They’re fast becoming a staple of home and municipal landscapes and parks due to their carefree attitude and showy, summer-long blossoms.
I have several Knock Out roses in my garden, and the most frequent comment is, “Wow, these things just don’t stop!” Knock Out roses don’t make the best cut flowers – they’re thin-stemmed and don’t last very long – but they’re lovely and sweetly fragrant in arrangements while they last.
Advantages of Knock Out Roses
- Shrub Roses: In general shrub roses are the most carefree of all rose types. Most Knock Outs grow about 3-4 feet high by 3-4 feet wide in a naturally compact, upright, round shape; although I’ve seen them sprawling upwards of 5 feet if they’re happy and unpruned.
- Hardy to Zone 5: In colder climates, Knock Out roses can be protected for the winter or brought indoors in pots.
- Long Blooming: Knock Out roses start blooming in spring and keep it up full tilt until well into fall.
- Disease Resistant: Knock Out roses are resistant to black spot and other diseases.
- Shade Tolerant: While roses are usually full-sun plants, Knock Out roses will tolerate some partial shade.
- Fast Growing: Within a month or two you’ll think these roses have always been there, and they’re quick to respond to pruning.
- Drought and Heat Tolerant: Once established, Knock Out roses can tolerate all but the most extreme heat and drought.
- Versatile: Knock Out roses can be used anywhere in the landscape, from roadside plantings to garden borders to containers and specimen plantings.
- Low Maintenance: Knock Out roses need very little care for season-long enjoyment.
Original Knock Out rose.
Knock Out Rose Varieties
There are several varieties of Knock Out roses to choose from:
- Knock Out: (Rosa ‘Radrazz’) The original variety, with single cherry-red to magenta blossoms.
- Double Knock Out: (Rosa ‘Radtko’) Also cherry-red, but with double blooms, and is a little more cold tolerant than the original.
- Pink Knock Out: (Rosa ‘Radcon’) Has single blossoms that is a light pink color.
- Pink Double Knock Out: (Rosa ‘Radtkopink’) Similar to pink, but with double blossoms.
- Rainbow Knock Out: (Rosa ‘Radcor’) Has pink single flowers with yellow centers. The plant is a little smaller than other varieties.
- Blushing Knock Out: (Rosa ‘Radyod’) This single-blossom variety is the palest pink of all.
- Sunny Knock Out: (Rosa ‘Radsunny’) A bright yellow rose with the most fragrance.
Pink Knock Out rose.
Growing Knock Out Roses
For best results, Knock Out roses need:
- Light: Knock Out roses do best in full sun or partial shade.
- Soil: Rich, well-draining soil means less maintenance!
- Pruning: Knock Out roses really are carefree (they don’t even need deadheading!), but if you want to keep them in top shape, cut them back pretty heavily in early spring – they’ll quickly fill back in with bud-covered branches. In addition to annual pruning, I also do an occasional shape-up as I’m cutting flowers, just to keep the plants symmetrical.
- Fertilizer: Feed about once a month from spring through late summer with a balanced organic fertilizer.
- Water: While Knock Out roses are drought tolerant, they’ll do best if watered every week or so.