A Knock Out rose in full flower, covered in cherry red blooms from spring into fall, looks like a plant that needs constant attention. It does not. This shrub rose asks for sun, well-drained soil and one yearly haircut, yet rewards that modest care with successive flushes of bloom.
What Is the Knock Out Rose?
Knock Out is a shrub rose, a medium shrub rather than a climber or a fussy hybrid tea. Bred in the United States in 1999 and introduced in 2000, it asks little of the person who plants it.
The flowers are medium-sized and single, with a open face rather than a tight many-petaled bud. The original color is cherry red, though the plant is now sold in multiple colors.
Blooms arrive in successive flushes through spring, summer and fall, so the shrub is not a one-week show. The flowers are also self-cleaning, which means you do not have to snip off every spent bloom to keep it looking tidy.
From the almanac
Roses in your state
The dates on this page depend on where you live. Your state's page carries its frost dates, its USDA zones and the year laid out month by month.
Northeast
Southeast
- Alabama
- Arkansas
- Delaware
- Florida
- Georgia
- Kentucky
- Louisiana
- Maryland
- Mississippi
- North Carolina
- South Carolina
- Tennessee
- Virginia
- West Virginia
Midwest
Southwest
West
Pacific Northwest
Canada
Where Does the Knock Out Rose Grow Best?
Knock Out is hardy in zones 5b-9, which covers a large share of the country, though conditions inside that range still differ from one region to the next. Pick the part of the country that sounds like yours.
- Upper Midwest and New England: Zone 5b is the cold edge of its stated hardiness range. Plant it in a sunny spot with well-drained soil.
- Mid-Atlantic and the Carolinas: These areas fall within the stated hardiness range. In North Carolina, it does fine with well-drained soil and plenty of sunlight.
- Texas and the Gulf Coast: Heat and dry spells are part of the deal, and the rose is drought tolerant. It is also described as virtually disease-free.
- Northern Plains and the high Rockies: Yards colder than zone 5b fall outside this rose’s stated hardiness range.
The state selector just below this section takes you to the page for your own state, with the months that fit where you live.
How to Care for the Knock Out Rose Through the Year
Waking Up
As spring warms, watch the canes for swelling buds. That swelling is your signal that the plant is stirring and that pruning time has arrived. Soil that drains well and a spot with plenty of sun do most of the work from here.
Pruning
Prune late in the winter, when the buds begin to swell. Doing it every year is the safer habit, though you might get away with pruning for size every other year.
A hard cut brings a strong growth response, and cutting the shrub back to around 18 inches is a routine approach in North Carolina. Hard pruning is used to prompt a strong growth response.
Bloom Season
The first flush comes in spring, followed by more in summer and fall. Because the blooms clean themselves, there is little to do except enjoy them. Keep the plant in full sun so it keeps producing.
Summer
Drought tolerance is the trait to lean on here. It also needs well-drained soil.
Fall
The last flush of bloom arrives in fall, so leave the shrub alone and let it finish. Resist the urge to cut it back now. Pruning waits until the buds swell late in winter.
Winter
Zone 5b is the cold edge of the rose’s stated hardiness range. Prune when the buds begin to swell late in winter.
Knock Out Rose Diseases and Weak Points
Knock Out is popular because pest and disease issues are very few. It is described as virtually disease-free and requires little to no maintenance.
That reputation rests on a few specific traits, laid out here.
| Threat | How Knock Out handles it |
|---|---|
| Black spot | Resistant |
| Drought | Tolerant |
| Spent flowers | Self-cleaning, no deadheading chore |
| Poor drainage | Needs well-drained soil to do well |
| Shade | Needs plenty of sunlight |
The weak points are really about the site rather than the plant. Soggy ground and too little sun are what hold it back, and a zone colder than 5b is a limit no amount of care will fix.
Is the Knock Out Rose Right for Your Yard?
It suits a sunny bed with soil that drains, and it suits people who want a low-maintenance rose. It is a good fit for beginners with roses. It does not suit shady corners, wet ground or yards colder than zone 5b.
- Your state page gives the months for pruning and care where you live, so open it before the buds begin to swell.
- Check the plant tag for the mature size before you choose a spot, then give the shrub room to fill out.
Common Questions
Does the Knock Out Rose Need Deadheading?
No. The blooms are self-cleaning, so spent flowers drop without help, and the shrub keeps making new ones.
Can You Prune a Knock Out Rose Every Other Year?
You might get away with pruning for size every other year, but a yearly cut is the better habit.
Will a Knock Out Rose Grow in a Cold Climate?
It is hardy in zones 5b-9. Colder than that, the plant is not reliably hardy, so check your zone before planting.