DOUBLE KNOCK OUT® – red landscape shrub rose – RADtko
Imagine stepping onto your coastal veranda to a drift of cherry-red blooms that seem to shrug off weather and busy weeks alike: DOUBLE KNOCK OUT® is bred for simplicity and modern gardens, offering steady colour with almost no fuss. This compact, bushy shrub keeps a tidy outline even in exposed, breezy spots, helping it stay firmly anchored while its dense, glossy foliage builds structure in small family plots. Flowers form in generous clusters that refresh themselves thanks to excellent self-cleaning, so there is no need for constant deadheading or detailed pruning. On hot, drying days it continues to flower once established, using water sensibly and coping well with coastal wind and occasional salt spray in well-drained soil, giving reassuring performance where rain and gusts can otherwise spoil the show. Plant once and enjoy its own-root reliability as it settles through year one, bulks up in year two and reaches full ornamental value by year three, delivering long-lived colour with minimal input. The vivid, slightly softened cherry-red tones feel naturally at home beside shingle, driftwood and sea-grass textures, while the semi-double blooms offer light pollinator interest without the need for intensive care, ideal when you value time for relaxation. For an easy, unfussy backbone to a coastal-inspired layout, this dependable rose brings lasting structure, reliable flowering and a quietly refreshing, seaside mood.
Usage options
| Target area | Reasoning |
|---|
| Coastal veranda container (40–50 litre) |
A sturdy, bushy habit and moderate height make DOUBLE KNOCK OUT® ideal for a single large pot on a veranda, where its continuous cherry-red clusters create a long season of colour with little intervention for busy coastal veranda owners. |
| Small family front garden bed |
Compact spread and low-maintenance self-cleaning flowers keep front gardens smart without weekly deadheading, giving reliable structure and colour that suits average UK plots and time-pressed homeowners seeking neatness for beginners with little spare time. |
| Wind-exposed, salt-tolerant shingle strip |
Dense foliage and a well-branched framework help it stay stable and attractive in coastal breezes, tolerating sun and wind where rain and gusts can otherwise spoil the show, making it a tough yet pretty choice for coastal-style garden lovers. |
| Low flowering hedge along a path |
Even growth and repeat-flowering clusters form a colourful, informal hedge that defines paths or drive edges without complex clipping, while own-root plants mature into long-lived, gap-free lines for homeowners wanting dependable structure. |
| Mixed border with grasses and perennials |
The softly radiant cherry-red flowers pair beautifully with sea kale, blue Festuca and lavender, giving a coastal feel and providing repeat colour between perennial flushes, with little extra care needed for informal family-garden planters. |
| Urban courtyard or patio pot (50 litre) |
Excellent disease resistance and good heat tolerance mean foliage stays healthy in sheltered, paved spaces, while its steady flowering adds cheer where watering and care must stay simple for busy urban balcony and patio gardeners. |
| Low-maintenance family play-area border |
Rounded, bushy plants with moderate thorns are easily kept within bounds, giving colour and greenery around lawns or play spaces without demanding constant pruning or spraying, suiting families wanting resilient, easy-care planting. |
| Public-facing driveway or parking edge |
Self-cleaning flowers and strong disease resistance keep the shrub tidy near cars and paths with minimal upkeep, while own-root vigour supports a long planting life and stable display that benefits homeowners who prefer plant-and-enjoy roses. |
Styling ideas
- Seaside-Strip Border – repeat DOUBLE KNOCK OUT® along shingle with sea kale and blue Festuca for a low, ribbon-like wind-resilient edge – for coastal-style enthusiasts.
- Tea-on-the-Veranda Pot – plant a single shrub in a 50 litre tub with gravel mulch and a low lavender rim for colour and scent near chairs – for relaxed afternoon tea lovers.
- Cherry-Red Hedge – create a gently curving, waist-high hedge along a path, underplanting with creeping thyme for softness and easy ground cover – for homeowners wanting simple structure.
- Urban-Courtyard Cluster – group three plants in generous containers with silvery grasses to bring long-season colour to paved spaces – for city gardeners seeking low-effort impact.
- Family-Mixed Border – weave plants between hydrangeas and soft perennials to anchor a child-friendly border with resilient, repeat red colour – for busy family-garden keepers.
Technical cultivar profile
| Parameter | Data |
|---|
| Name and registration |
Modern shrub rose, registered as RADtko, marketed as Double Knock Out® within the Knock Out® Collection; ARS exhibition name Double Knock Out®, part of the bed and landscape shrub group. |
| Origin and breeding |
Bred by William J. Radler in the USA around 2000 from ‘Bucbi’ seedling × ‘Razzle Dazzle’ seedling, introduced and registered in 2004 by Conard-Pyle (Star® Roses and Plants). |
| Awards and recognition |
Australian Gold Medal 2004; UC Davis WUCOLS Blue Ribbon™ 2017; AGRS Regional Award 2018; A.R.T.S. Master Rose 2019, highlighting sustainable performance and landscape reliability. |
| Growth and structural characteristics |
Bushy, rounded shrub 85–115 cm high and wide with dense, slightly glossy dark purplish-green foliage; moderately thorny stems and good self-branching create a compact, landscape-suited outline. |
| Flower morphology |
Semi-double, cup-shaped cherry-red blooms, 1.5–2.75 inches across with 13–25 petals, freely borne in clusters; remontant habit with abundant repeat flowering through the season and good self-cleaning. |
| Colour data and phenology |
Vibrant cherry-red, ARS mr; RHS 53C outer, 53A inner petals; buds deep cherry-red, blooms soften gradually toward pinkish tones in strong sunlight, giving a lively yet harmonious garden presence. |
| Fragrance and aroma |
Very weak, barely perceptible scent described as a light sweet-fruity note; chosen primarily for visual impact, reliability and ease rather than strong fragrance, suiting low-maintenance landscape plantings. |
| Hip characteristics |
Hip set is usually sparse; when present, small spherical hips 6–10 mm across, orange-red in colour, may appear, adding a modest late-season decorative touch without significant self-seeding. |
| Resistance and winter hardiness |
RHS H7, USDA Zone 5b, Swedish Zone 4; reliably hardy to around -26 °C with strong resistance to powdery mildew, black spot and rust, plus good heat and moderate drought tolerance once established. |
| Horticultural recommendations |
Suited to beds, edging, hedges, containers and shrub groups; spacing 60–110 cm depending on use, 2.0–2.3 plants/m² in mass plantings; thrives in full sun or light shade with free-draining soil. |
DOUBLE KNOCK OUT® offers continuous cherry-red colour, self-cleaning flowers and excellent disease resistance in a long-lived own-root form; consider it as a dependable, low-effort highlight for your coastal or family garden.
