KNOCK OUT® – cherry-red landscape shrub rose - Radler
If You would like a reliable, unfussy rose that simply gets on with flowering in an Irish family garden, KNOCK OUT® is designed for exactly that. This compact modern shrub keeps a steady display of cherry-red blooms from early summer, shedding its spent flowers cleanly so You avoid constant deadheading. It shrugs off common fungal problems even in our damp weather, giving You reassuringly healthy foliage with little fuss. Own-root plants settle in steadily for a long life in the garden, coping well with Atlantic wind and frequent rain when good drainage is provided on heavier soils. In borders or small groups it forms a bushy, rounded shape that suits front gardens and cottage-style beds. Once planted and watered in, its low maintenance needs, good heat and short-drought tolerance and strong urban resilience make it an easy partner for busy lifestyles. Over the first few years it builds roots, then top growth, before rewarding You with full impact in the third season.
Use cases
| Target area |
Reason |
| Front garden focal shrub |
Bushy, rounded habit to about 90–120 cm makes an eye-catching yet tidy front-garden feature that does not overwhelm smaller spaces, with flowers presented at a perfect height for everyday enjoyment for the busy home gardener beginner |
| Low-maintenance flowering bed |
Exceptional disease resistance and minimal pruning needs make this rose ideal where You want colour without complicated care, keeping maintenance light while still delivering a long flowering season and dependable garden performance for the relaxed gardener homeowner |
| Urban front or courtyard planting |
Proven tolerance of heat, reflected light and urban stress allows KNOCK OUT® to thrive beside drives, paths and pavements, maintaining healthy foliage and flower show even with some neglect for time-pressed city dwellers urbanites |
| Small rose group in family garden |
Planted in groups of 3–5 at recommended spacing, the bushy shrubs knit together into a continuous cherry-red display, ideal beside a lawn or patio where children play and the aim is cheerful colour with simple upkeep for family gardens parents |
| Mixed border with perennials |
Clustered, remontant flowering and mid-green foliage combine well with cottage favourites, giving a season-long red accent among perennials without needing frequent shaping, ideal for informal, relaxed mixed borders for cottage-style lovers gardeners |
| Coastal or exposed sites |
Sturdy growth and strong overall toughness cope well where gardens meet brisk Atlantic winds and frequent showers, so with sensible drainage this rose remains stable and floriferous in challenging spots for coastal and rural plot owners coast-dwellers |
| Container on patio or balcony |
Compact, dense structure suits a large 40–50 litre container, where it provides months of colour close to seating; own-root plants adapt well to pot culture and recover reliably after winter for balcony and terrace gardeners container-owners |
| Easy-care long-term planting |
As an own-root shrub that spends its first year building roots, its second on bushy framework and the third on full display, it develops into a stable, regenerating plant that keeps its ornamental value for many seasons for long-term planners planners |
Decorating ideas
- Cottage-Red Welcome – Plant a trio by the front path with sweet alyssum edging for a soft, cottage feel and a scented, bee-friendly carpet – perfect for homeowners who want charm without complex planting plans.
- Urban Cherry Border – Line a short drive or townhouse front bed with evenly spaced shrubs and underplant with low Artemisia for silver contrast – ideal for urbanites seeking structure and easy colour.
- Family Play-Garden Corner – Place a small group beside the lawn, backed by cherry laurel for privacy and year-round green – suited to families wanting robust, forgiving plants near outdoor play areas.
- Patio Accent Pot – Grow one plant in a 40–50 litre terracotta container, adding trailing lobularia around the rim for softness – good for balcony and patio users keen on colour without heavy maintenance.
- Relaxed Mixed Bed – Combine KNOCK OUT® with lavender, hardy geraniums and ornamental grasses to weave red highlights through a naturalistic border – best for gardeners who enjoy an informal but reliable display.
Technical cultivar profile
| Characteristic |
Data |
| Name and registration |
Modern shrub rose, landscape type; registered as RADrazz, marketed as Knock Out®; part of the Knock Out® collection; approved exhibition name Knock Out® for American Rose Society listings. |
| Origin and breeding |
Bred by William J. Radler in the USA from ‘Carefree Beauty’ × ‘Razzle Dazzle’; breeding year 1988, registered 1999 and commercially introduced in 2000 via Conard-Pyle / Star Roses. |
| Awards and recognitions |
All-America Rose Selections winner 2000; ADR Award Germany 2002; Portland Gold Medal 2003; American Rose Society David Fuerstenberg Prize 2003; World Federation of Rose Societies Hall of Fame 2018. |
| Growth and structure |
Bushy, rounded shrub reaching about 90–120 cm in both height and spread; dense, mid-green, slightly glossy foliage; moderately thorny stems; suitable for beds, groups, low hedging and landscape use. |
| Flower morphology |
Semi-double, cup-shaped flowers with around 13–25 petals; large blooms borne in clusters; remontant habit with generous repeat, including a notable second flush in suitable conditions. |
| Colour and phenology |
Cherry-red blooms with a subtle pinkish tone; darker buds open bright, then gradually fade lighter in strong sun or heat; colour remains more vivid in cooler weather, giving an evolving display through the season. |
| Fragrance and aroma |
Fragrance is very weak and often barely noticeable, so the rose is chosen primarily for colour, health and flowering performance rather than scent; semi-double, open-centred blooms offer moderate pollinator appeal. |
| Rose hip characteristics |
Strong self-cleaning habit means hips are usually sparse; when present they are small, spherical, orange-red hips about 7–11 mm in diameter, adding only a light autumn accent. |
| Resistance and hardiness |
Excellent resistance to black spot, powdery mildew and rust; hardy to approximately −32 to −29 °C (USDA zone 4b, RHS H7, Swedish zone 5); tolerates heat and brief drought but prefers watering in prolonged dry spells. |
| Horticultural recommendations |
Low maintenance shrub for beds, borders, parks and urban plantings; suitable in full sun to partial shade; space 55–100 cm depending on use; best in well-drained soil with basic feeding and only light annual pruning. |
KNOCK OUT® offers reliable cherry-red flowering, outstanding disease resistance and easy long-term growth as an adaptable own-root shrub, so You can plant with confidence and enjoy a long-lived, low-effort feature in your garden.
