KNOCK OUT® – cherry-red landscape shrub rose - Radler
Imagine summer afternoons in a relaxed cottage-style garden where KNOCK OUT® surrounds your seating with continuous cherry-red bloom, even in exposed, breezy spots with challenging weather and soil. This modern shrub rose is bred for straightforward maintenance, with naturally bushy structure and reliable repeat flowering that keeps beds and low hedges colourful from early season to frost. As an own-root plant it offers reassuring longevity, recovering well from winter, pets or pruning experiments, and gaining strength each year as roots establish, shoots build up and the full garden-worthy display emerges by the third season. Its dense mid-green foliage and neat habit work beautifully in small to medium family gardens, from front drives to kitchen-garden paths, giving you relaxed, romantic colour with minimal effort.
Usage options
| Target area |
Reasoning |
| Front garden border along the path or drive |
The compact, bushy habit and continuous cherry-red flowers create an instant welcome without blocking views or paths, and the self-cleaning blooms mean little deadheading by the door; ideal for the time-poor but style-conscious homeowner |
| Low flowering hedge dividing garden “rooms” |
Regular repeat flowering and dense branching allow you to form a soft boundary that stays colourful for months; the rose tolerates basic trimming or more formal shaping, suiting families who like clear structure yet romantic planting, especially the relaxed gardener |
| Cottage-style mixed bed with perennials |
Clusters of semi-double cherry-red flowers sit above mid-green foliage and combine easily with cottage perennials, giving a traditional look without fussy care; own-root toughness ensures the shrub knits into the border for years, pleasing lovers of informal planting |
| Urban courtyard or front-of-house planting |
Bred for robust urban tolerance, this rose copes well with heat, reflected sun and short dry spells once established, keeping its shape and colour on busy streets; an excellent choice where watering time is limited for the busy city-based owner |
| Large container on terrace or patio (40–50 L+) |
Its rounded, compact growth and continuous flowering suit a generous pot near seating, provided a 40–50 litre container and regular watering are given; own-root resilience allows long-term container use with simple pruning, appreciated by balcony or patio gardeners |
| Family play garden with low-maintenance planting |
Good disease resistance and minimal feeding needs keep care simple, while reliable flowering adds colour near lawns or play areas; the shrub shape is easy to prune back from footballs or footfall, making it practical for busy family-focused buyers |
| Coastal or exposed suburban plots |
The sturdy, well-anchored root system and bushy structure cope well with wind, and the foliage holds up in typical British rain and changeable conditions, offering dependable cover and colour in open gardens, which particularly suits coastal and edge-of-town households |
| Kitchen-garden edges and productive plots |
Semi-double, open-centred blooms attract bees, supporting pollination in nearby fruit and veg while adding a storybook cottage feel; long-lived, own-root shrubs gradually build into a low hedge framing beds, ideal for wildlife-aware kitchen-garden enthusiasts |
Styling ideas
- Cottage-ribbon – Run a loose line of KNOCK OUT® along a path, weaving between lavender and sweet alyssum to emphasise its continuous flowering – for romantic border lovers
- Cherry-hedge – Create a low hedge at 55–65 cm spacing, underplant with hardy geraniums for a soft edge that highlights the dense structure – for families wanting gentle garden “rooms”
- Kitchen-frame – Edge veg beds with KNOCK OUT® and herbs like chives and thyme, letting its bee-friendly open blooms support pollination – for practical kitchen-garden keepers
- Urban-duet – In a 50 L terracotta pot, pair with silver Artemisia and gravel mulch to celebrate its drought tolerance and compact form – for busy city balcony or patio owners
- Front-garden-focus – Plant a small group by the gate with soft grasses to showcase the self-cleaning cherry-red clusters as an effortless focal point – for low-maintenance front-garden designers
Technical cultivar profile
| Parameter |
Data |
| Name and registration |
Modern landscape shrub rose; registered as RADrazz, marketed as Knock Out®. Part of the Knock Out® collection, ARS exhibition name Knock Out®, used mainly as a shrub or bed rose. |
| Origin and breeding |
Bred in the USA by William J. Radler in 1988 from ‘Carefree Beauty’ × ‘Razzle Dazzle’; introduced 1999–2000 via Conard-Pyle and Star Roses as a robust landscape shrub. |
| Awards and recognition |
Holder of major international awards, including AARS (2000), ADR Germany (2002), Portland Gold Medal (2003) and WFRS Rose Hall of Fame induction in 2018 for enduring garden merit. |
| Growth and structural characteristics |
Bushy, rounded shrub typically 90–120 cm high and wide, with dense mid-green, slightly glossy foliage and moderate prickles; self-cleaning habit keeps the plant tidy with minimal pruning. |
| Flower morphology |
Semi-double, cup-shaped blooms with 13–25 petals, large-flowered clusters on short stems; generously remontant with a strong second flush, maintaining a colourful display through the season. |
| Colour data and phenology |
Cherry-red flowers (RHS 53B–53C), darkest in bud, bright on opening, fading slightly in heat; colour remains richer in cooler weather, providing medium colour retention over repeated flushes. |
| Fragrance and aroma |
Fragrance is very weak and barely noticeable, making it suitable where scent is not essential; emphasis is on visual effect, flowering continuity and reliability rather than aromatic display. |
| Hip characteristics |
Rose-hip formation is scarce due to strong self-cleaning; occasional small, spherical orange-red hips 7–11 mm may form, but generally the shrub stays free of noticeable fruit. |
| Resistance and winter hardiness |
Excellent disease resistance to black spot, mildew and rust; hardy to about −29 to −32 °C (RHS H7, USDA 4b, Swedish zone 5), with good heat and brief drought tolerance in UK gardens. |
| Horticultural recommendations |
Low-maintenance shrub for beds, borders, hedging and urban landscapes; prefers well-drained soil, tolerates partial shade, and needs only light annual pruning and modest feeding to perform well. |
KNOCK OUT® offers continuous cherry-red flowering, robust disease resistance and durable own-root strength, giving long-lived colour in family gardens with minimal fuss, so you can choose it with confidence for easygoing cottage-style planting.
