KNOCK OUT® – cherry-red landscape shrub rose - Radler
Imagine returning from the seaside, sand still on your shoes, and settling beside a sheltered screen of cherry-red blooms: KNOCK OUT® is a reliable, modern shrub rose that shrugs off wind, coastal air and variable British summers with ease. Its self-cleaning flowers fall away neatly, so You spend more time relaxing with tea and less time dead-heading. Bushy, compact growth makes it ideal for average family plots and small front gardens, where it anchors beds and low hedges without becoming overbearing. As an own-root plant, it builds a deep, resilient rootstock for a long-lived display in containers of at least 40–50 litres or open ground, settling securely even where drainage and rainfall demand thoughtful water management. In its first year it concentrates on roots, the second on leafy shoots, and by the third it offers its full, generous ornamental performance.
Usage options
| Target area | Reasoning |
|---|
| Coastal veranda in Cornwall or Devon |
KNOCK OUT® copes well with brisk, salty air and exposed positions, providing a cheerful cherry-red backdrop to shingle pots and sea-themed seating. In a 40–50 litre container it remains stable and easy to manage for beginners. |
| Small front garden hedge |
The bushy, even growth habit and moderate height make this rose a neat, low hedge along drives or paths, giving structure without blocking light. Spacing at around 55 cm creates a dense line valued by homeowners. |
| Mixed family border in a suburban garden |
Its continuous, remontant flowering and compact spread suit typical family borders, where dependable colour is needed with little fuss. Strong own-root vigour keeps the display balanced and long-lasting for busy gardeners. |
| Low-maintenance bed in urban settings |
High disease resistance and good heat tolerance mean fewer chemical treatments and less watering in paved, heat-prone spaces, while self-cleaning flowers keep beds looking fresh and tidy for time-poor households. |
| Informal shrub group in heavy, moisture-retentive soil |
Its robust root system anchors the plant securely and makes good use of heavier soils, as long as basic drainage is in place to handle periods of intense rainfall and shifting moisture levels for cautious planters. |
| Pollinator-friendly corner near a seating area |
Semi-double, open-centred blooms provide easy access for bees, adding gentle movement and ecological value around a bench or veranda rail, especially when paired with other nectar plants appreciated by eco-conscious families. |
| Statement specimen in a large patio container |
In a sizeable 40–50 litre pot, its dense foliage and repeat-flowering habit give a strong focal point on sun-trap patios, with minimal pruning needed each year, ideal for relaxed veranda-owners. |
| Long-season colour in public or shared spaces |
Designed as a landscape shrub, KNOCK OUT® offers long, reliable flowering with limited maintenance, making it suitable for shared entrances, communal gardens and low-input schemes valued by practical residents. |
Styling ideas
- Shingle-border breeze – Plant along a gravel or shingle strip with sea kale and blue Festuca for a soft coastal palette – ideal for seaside-loving families.
- Cherry-veranda pots – Use one plant per 50 litre container with trailing Lobularia maritima to soften edges – suited to balcony and veranda dwellers.
- Easy-hedge charm – Create a low cherry-red hedge along paths, underplanted with lavender for fragrance – perfect for busy homeowners.
- Pollinator nook – Combine KNOCK OUT® with herbs and simple daisies by a bench to attract bees – appealing to eco-aware beginners.
- Urban-ruby block – Mass-plant in small city front gardens for bold colour against brick or render – great for low-maintenance city plots.
Technical cultivar profile
| Characteristic | Data |
|---|
| Name and registration |
Modern shrub rose registered as RADrazz, marketed as Knock Out®, a cherry-red landscape shrub rose in the Knock Out® collection, with ARS exhibition name Knock Out®. |
| Origin and breeding |
Bred by William J. Radler in the USA (1988) from ‘Carefree Beauty’ × ‘Razzle Dazzle’; registered 1999, introduced 2000 by Conard-Pyle and Star Roses. |
| Awards and recognition |
AARS winner 2000, ADR Germany 2002, Portland Gold Medal 2003, ARS David Fuerstenberg Prize 2003, WFRS Hall of Fame 2018, widely recognised for landscape performance. |
| Growth and structural characteristics |
Bushy, compact shrub 90–120 cm high and wide, with dense, slightly glossy mid-green foliage, moderately thorny stems and a rounded habit suited to beds, hedges and containers. |
| Flower morphology |
Semi-double, cup-shaped blooms with 13–25 petals, large-flowered clusters on short stems; remontant habit with a generous second flush and good self-cleaning of spent flowers. |
| Colour data and phenology |
Cherry-red blooms, ARS MR, RHS 53B outer and 53C inner; colour is bright on opening, may fade lighter in heat, remaining more vivid and even in cooler conditions across the season. |
| Fragrance and aroma |
Very weakly scented, with barely noticeable fragrance; grown primarily for strong landscape colour and foliage effect rather than perfume, so best paired with aromatic companions if scent is desired. |
| Hip characteristics |
Rose hips are rarely produced due to strong self-cleaning; occasional small spherical orange-red hips, about 7–11 mm in diameter, may appear late in the season. |
| Resistance and winter hardiness |
Excellent disease resistance to black spot, powdery mildew and rust; hardy to around –32 to –29 °C (RHS H7, USDA 4b), with good heat and short-term drought tolerance when established. |
| Horticultural recommendations |
Suited to flower beds, borders, hedges, groups and urban schemes; plant 55–65 cm apart, 2.4–2.7 plants/m²; low maintenance, requiring only light pruning and modest feeding in spring. |
KNOCK OUT® offers reliable cherry-red colour, low-maintenance self-cleaning flowers and robust, long-lived own-root growth, making it a thoughtful choice for relaxed, easy-care coastal and family gardens.
