DOUBLE KNOCK OUT® – red landscape shrub rose – Radler
Imagine stepping outside for a short walk in soft rain, the air cool and clear, and your front garden glowing with cherry blooms against dark leaves. DOUBLE KNOCK OUT® is bred for effortless colour in real Irish conditions, coping calmly with frequent rain and heavy soil that needs good drainage. This modern shrub rose gives remarkably long, repeat flowering from early summer to late season, with self-cleaning clusters that drop their spent petals without fuss. Its naturally bushy habit forms a rounded, tidy shape that suits both Dublin terraces and country cottages, while the semi-double blooms still leave room for visiting bees. As an own-root plant, it builds strength steadily below ground, so over time it offers a reassuringly long lifespan, reliable regrowth after harsh winters, and low-maintenance ease for busy gardeners.
Usage options
| Target area | Reasoning |
|---|
| Front garden focal shrub |
Planted as a single shrub, DOUBLE KNOCK OUT® quickly creates a neat, bushy mound that draws the eye from the pavement, with cherry-red flowers that keep returning through the season; ideal for a welcoming look with little ongoing work for beginners. |
| Casual low hedge along paths or drives |
At 60 cm spacing, its dense foliage and steady flowering line a path with soft structure rather than a formal barrier, while the good disease resistance means no complicated spraying regime, even in damp coastal air, suiting busy-owners. |
| Mixed cottage-style border |
The warm red clusters blend beautifully with cottage favourites like clematis or hydrangea, and the remontant flowering keeps colour going between perennials, so once the roots establish you gain fuller shoots and showier display over three seasons, pleasing romantics. |
| Urban and street-side plantings |
Selected worldwide for tough urban use, this rose copes well with reflected heat, moderate drought once established and limited soil volumes, so small Irish front gardens and on-street beds stay cheerful without frequent watering, reassuring city-gardeners. |
| Low-maintenance family flowerbed |
Self-cleaning flowers reduce deadheading, and its strong resistance to black spot, mildew and rust means less time worrying about spraying, keeping the bed looking presentable even when life is busy for time-poor. |
| Pollinator-friendly accent in a small garden |
Semi-double blooms with accessible stamens offer occasional forage for visiting bees without the messy look of spent flowers hanging on, making it a gentle way to add wildlife interest near windows or seating for nature-lovers. |
| Container planting on patio or terrace |
In a large 40–50 litre pot with good drainage, this bushy shrub forms a rounded, colourful presence by the front door or seating area, rewarding simple watering and feeding with months of flowers for balcony-owners. |
| Informal shrub group or mass planting |
Planted at the recommended densities, it knits into a flowing mass of foliage and red blossom that stays attractive despite frequent Irish showers and soil that needs careful drainage, giving professional-looking results at home for homeowners. |
Styling ideas
- Cottage-Ribbon – Run a loose line of shrubs along a picket fence with foxgloves and hardy geraniums weaving through for a soft cottage feel – ideal for romantic beginners.
- Terrace-Welcome – Place one shrub in a tall 50 litre container by your front step, underplanted with trailing ivy and white violas – perfect for busy city-gardeners.
- Ruby-Carpet – Mass-plant several bushes in a sunny front bed to create a low, red “carpet” that looks designed yet informal – great for low-maintenance homeowners.
- Contrast-Glow – Pair with dark foliage shrubs like Cotinus ‘Royal Purple’ so the cherry-red flowers pop against rich purple leaves – suited to design-conscious enthusiasts.
- Family-Corner – Build a cheerful play-area backdrop with DOUBLE KNOCK OUT® in front of climbing hydrangea and clematis for layered greenery and colour – appealing to young families.
Technical cultivar profile
| Property | Data |
|---|
| Name and registration |
Modern shrub rose, registered as RADtko; marketed as Double Knock Out®, a cherry-red landscape rose within the Knock Out® collection, approved exhibition name Double Knock Out®. |
| Origin and breeding |
Bred by William J. Radler in the United States from ‘Bucbi’ × ‘Razzle Dazzle’ seedlings; introduced and distributed by Conard-Pyle (Star® Roses and Plants) from 2004. |
| Awards and recognition |
Australian Gold Medal 2004; American Garden Rose Selections Regional Award 2018; A.R.T.S. Master Rose 2019; UC Davis WUCOLS Blue Ribbon 2017 for landscape performance. |
| Growth and structural characteristics |
Rounded, bushy habit reaching about 85–115 cm in height and spread, with dense, slightly glossy purplish-green foliage and moderate prickliness, forming a compact, well-filled shrub. |
| Flower morphology |
Semi-double, cup-shaped clusters of medium-sized 4–7 cm flowers with 13–25 petals; remontant habit provides abundant first bloom followed by strong repeat flushes through the season. |
| Colour data and phenology |
Vibrant cherry-red flowers, ARS mr; RHS 53C outer, 53A inner; buds deep cherry-red, ageing gradually to a softer pinkish-red in strong sunlight while maintaining overall warm red impact. |
| Fragrance and aroma |
Very light, barely perceptible scent with a gentle sweet, fruity character; grown primarily for its continuous colour and landscape effect rather than for strong fragrance performance. |
| Hip characteristics |
Generally sparse hip set; occasional small spherical hips 6–10 mm across, orange-red in colour, adding modest late-season interest without significantly affecting flowering continuity. |
| Resistance and winter hardiness |
Excellent resistance to black spot, powdery mildew and rust; hardy to approximately −26 to −23 °C (USDA 5b, RHS H7), with good tolerance of heat and moderate drought when established. |
| Horticultural recommendations |
Best in well-drained soil with regular moisture; suitable for flowerbeds, hedges, groups, parks and large containers; plant 60–110 cm apart depending on hedge, mass planting or specimen use. |
DOUBLE KNOCK OUT® offers months of cherry-red colour, bushy low-maintenance growth and long-lived own-root reliability, making it a thoughtful choice for effortless structure and brightness in family gardens.
