DOUBLE KNOCK OUT® – red landscape shrub rose – RADtko
If You want a rose that simply works in everyday Irish conditions, Double Knock Out® gives You generous cherry-red flowers on a compact, bushy shrub that shrugs off rain and wind and copes well with heavy soil as long as drainage is improved. It flowers repeatedly from early summer to autumn, the clusters refreshing themselves thanks to its naturally self-cleaning habit, so You spend more time enjoying and less time deadheading. Its foliage is remarkably healthy, with reliable resistance to common fungal diseases that often trouble roses in our humid climate, supporting a long, low-maintenance life in the garden. As an own-root plant it grows into a stable, well-shaped shrub that recovers more easily from pruning or winter damage, keeping its ornamental value over many years. Semi-double blooms with a lightly open centre offer moderate interest for pollinators while still providing that full, romantic colour effect from a distance. Ideal for busy households, it is equally at home in front gardens, small beds or large containers, settling in reliably if You provide regular watering in the first season. Think of it as a friendly, forgiving partner in Your planting plans – roots in year one, fuller shrub in year two, and a truly completed garden look by year three, giving You confidence even if You are a complete beginner. Its award-winning performance in demanding urban landscapes translates directly into dependable garden ease for You.
Use cases
| Target area | Reason |
|---|
| Front garden focal shrub |
The compact, bushy habit and continuous cherry-red flowering make it perfect beside a driveway or front path, providing a tidy, welcoming look without complicated pruning or feeding routines, ideal for a time-poor homeowner |
| Low-maintenance bed in family garden |
With excellent disease resistance and good self-cleaning, it keeps beds looking fresh with minimal deadheading, so You can enjoy months of colour even in wet summers without constantly treating or fussing over the plants, suiting the relaxed gardener |
| Small hedge or boundary line |
Planted 60 cm apart, it forms a dense, flowering, shoulder-height line that clearly defines paths or garden boundaries while staying easy to trim back once a year, perfect for those wanting soft structure rather than high-maintenance formality, appealing to the practical planner |
| Mixed cottage-style border |
Its vibrant red clusters stand out among perennials and shrubs such as lavender or catmint, and the semi-double flowers add a gentle, pollinator-friendly element without dominating the planting, making it attractive for fans of informal, romantic borders |
| Urban and roadside planting |
Bred and proven for demanding landscape use, it tolerates heat, reflected light and lower upkeep, keeping its good leaf cover and flower show in public-facing spots where regular care is limited, a reassuring choice for shared frontages and communal spaces |
| Coastal or exposed Irish sites |
Its sturdy framework and reliable health cope well where wind and driving rain meet heavier soils, as long as drainage is improved, providing colour where many plants struggle, which suits coastal villagers and exposed-estate gardens |
| Large container on patio or balcony |
In a 40–50 litre pot with quality compost, it builds a compact, floriferous shrub that decorates seating areas from early summer onwards, allowing You to enjoy real garden impact even in paved spaces, ideal for apartment or townhouse dwellers |
| Small rose group for strong colour impact |
Planting 3–5 together at recommended spacing quickly creates a bold, long-season block of red that looks designed yet easygoing, maturing from simple young plants to a full, coherent display over the first three years, rewarding the patient beginner |
Decorating ideas
- Cherry-Red Welcome – Line the front path with a short Double Knock Out® hedge underplanted with white alyssum for a bright, low-care entrance – perfect for busy families
- Country Cottage Mix – Combine with lavender and foxgloves in a loose border so the red blooms pop among soft purples and spires – ideal for cottage-garden lovers
- Patio Feature Pot – Plant one shrub in a 40–50 litre terracotta container and circle the rim with trailing thyme for scent and texture – great for balcony and terrace users
- Urban Colour Block – Group three shrubs with dark-leaved heucheras and ornamental grasses to create a modern, low-maintenance city planting – suited to contemporary homeowners
- Family-Friendly Corner – Place Double Knock Out® with a small hydrangea and spring bulbs to give layered interest without complicated care – ideal for beginner gardeners
Technical cultivar profile
| Parameter | Data |
|---|
| Name and registration |
Modern Shrub (Landscape Shrub) rose, registered as RADtko, marketed as Double Knock Out® within the Knock Out® collection; ARS exhibition name Double Knock Out®, commercial bed and landscape shrub type. |
| Origin and breeding |
Bred in the United States by William J. Radler from ‘Bucbi’ × ‘Razzle Dazzle’ seedlings; introduced 2004 by Conard-Pyle (Star Roses and Plants), CP Delaware Inc, with US plant patent granted in 2006. |
| Awards and recognitions |
Winner of Australian Gold Medal 2004; American Garden Rose Selections Regional Award 2018; A.R.T.S. Master Rose 2019; UC Davis WUCOLS Blue Ribbon 2017, confirming strong performance and reliability in trials. |
| Growth and structure |
Forms a bushy, rounded shrub 85–115 cm high and wide, with dense, slightly glossy dark purplish-green foliage and moderate prickles, creating a full, landscape-suitable plant that reads as a compact flowering mound. |
| Flower morphology |
Semi-double to lightly full flowers with 13–25 petals, cup-shaped and cluster-flowered; medium size at roughly 4–7 cm, produced continuously in flushes, with most spent blooms dropping cleanly to maintain a neat appearance. |
| Colour and phenology |
Vibrant, pure cherry-red blooms, deeper towards the centre, opening from deep cherry buds; colour may lighten towards pinkish red in strong sun, yet overall effect remains a warm, clear red through the main flowering period. |
| Fragrance and aroma |
Fragrance is very weak, with only a barely perceptible sweet fruity note on close inspection; chosen primarily for ornamental colour, flower production and health rather than for strong scent in the garden. |
| Rose hip characteristics |
Usually sparse hip set; occasionally forms small, spherical hips about 6–10 mm in diameter, orange-red in colour, which can add light ornamental interest in late season without creating heavy seeding. |
| Resistance and hardiness |
High resistance to black spot, powdery mildew and rust; hardy to around −23 to −26 °C (RHS H7, Swedish Zone 4, USDA 5b), tolerating heat and moderate drought once established, suitable for robust, low-input plantings. |
| Horticultural recommendations |
Best in fertile, well-drained soil with sun or light partial shade; space 60–110 cm depending on hedge or specimen use; water well in year one, then maintain with simple annual pruning, feeding and mulching in spring for sustained performance. |
DOUBLE KNOCK OUT® offers months of vivid red colour, healthy, low-maintenance growth and the long-term stability of an own-root shrub, making it a dependable choice for an easy, rewarding garden that You can select with confidence.
