DOUBLE KNOCK OUT® – red landscape shrub rose - Radler
DOUBLE KNOCK OUT® is an easy-going, modern shrub rose designed for impact in everyday British gardens, giving months of cherry-red colour with very little effort. This bushy, compact variety is naturally resilient, with excellent resistance to common rose diseases, so it stays looking tidy even in damp summers and breezy, exposed spots with challenging weather. The flowers are self-cleaning, so spent blooms drop away and the plant quickly sends up new clusters, keeping front gardens and small beds bright without constant deadheading. As an own-root plant it grows into a stable, long-lived structure, recovering well after pruning or harsher winters and maturing steadily in a simple rhythm of Year 1 roots, Year 2 shoots, Year 3 full ornamental value. Suitable for partial shade and containers as well as borders, it is an excellent choice if you want a reliable red rose that you can plant, water in, and let it get on with the job.
Usage options
| Target area |
Reasoning |
| Front garden focal shrub |
The rounded, bushy habit and continuous cherry-red flowering give a neat, eye-catching focal point by the front path or doorway with little maintenance beyond basic watering and a light annual prune, ideal for those who simply want dependable colour all season, especially beginners. |
| Small bed or mixed border |
Its compact 85–115 cm height and spread fit well in modest beds and classic cottage-style borders, where repeat flowering keeps the scene lively without labour-intensive care, suiting gardeners who like a tidy look but have limited time, particularly homeowners. |
| Low-maintenance flowering hedge |
Planted at around 60 cm centres, the dense foliage and regular flushes of bloom create an informal, low hedge that screens edges and boundaries while needing only occasional trimming, attractive for those wanting structure and colour without fiddly shaping, especially families. |
| Urban and street-facing gardens |
This rose tolerates heat, reflective surfaces and moderate drought once established, while its strong disease resistance and self-cleaning flowers keep it looking fresh even when garden access is limited, ideal for busy city plots where weekend care is the norm and suits time-pressed commuters. |
| Large containers and patio planters |
In a 40–50 litre or larger container, its bushy shape and constant bloom provide a generous splash of red on patios or balconies, with simple care based mainly on watering and feeding, making it well suited to paved spaces and compact gardens used by urban residents. |
| Low-care cottage-style group planting |
Planted in groups of 3–5, the uniform height, cherry-red colour and good health build a classic cottage feel without complex combinations, and minimal deadheading is needed thanks to the self-cleaning habit, a reassuring choice for aesthetically minded but hesitant novices. |
| Tough family garden bed |
Good heat and drought tolerance, strong disease resistance and a sturdy frame mean it copes well with children, pets and everyday use, maintaining colour through the season even when conditions are less than ideal, which is helpful for practical, low-effort gardeners. |
| Partially shaded borders or corners |
Its ability to flower reliably in partial shade and perform well even in cooler, more humid parts of the garden broadens planting options, making awkward side-return beds or north-east facing spots more colourful and inviting for resourceful but busy owners. |
Styling ideas
- Cottage Duo – Combine with soft pink perennials and white foxgloves in a small bed for continuous colour and a relaxed front-garden feel – ideal for cottage-garden enthusiasts.
- Patio Anchor – Plant singly in a 50-litre terracotta pot by the front door, underplanted with low silver foliage for a strong yet easy-care focal point – ideal for busy urban homeowners.
- Cherry Hedge – Line a path with a loose hedge, interplanting with lavender for scent and contrast while keeping upkeep simple – ideal for families wanting structure and colour.
- Urban Contrast – Pair with dark-leaved shrubs like Cotinus ‘Royal Purple’ in a small border for bold colour contrast that still copes with city conditions – ideal for design-conscious city gardeners.
- Shaded Corner Lift – Use 3 plants in a triangle in a lightly shaded border with ferns and hostas to brighten a difficult corner – ideal for owners reclaiming awkward garden spaces.
Technical cultivar profile
| Parameter |
Data |
| Name and registration |
Modern shrub rose, landscape type; registered as RADtko, marketed as Double Knock Out®, part of the Knock Out® collection, for bed and landscape plantings. |
| Origin and breeding |
Bred by William J. Radler in the United States from ‘Bucbi’ and ‘Razzle Dazzle’ seedlings; introduced in 2004 by Conard-Pyle (Star® Roses and Plants). |
| Awards and recognition |
Australian Gold Medal 2004, AGRS Regional Award 2018, A.R.T.S. Master Rose 2019, and UC Davis WUCOLS Blue Ribbon™ 2017 highlight reliability and landscape performance. |
| Growth and structural characteristics |
Bushy, compact shrub 85–115 cm high and wide, with dense, slightly glossy dark purplish-green foliage and moderate prickliness, forming a rounded, well-filled garden presence. |
| Flower morphology |
Semi-double, cup-shaped flowers with 13–25 petals in clusters, medium-sized at roughly 4–7 cm, repeating strongly with abundant second and subsequent flushes through the season. |
| Colour data and phenology |
Vibrant cherry-red blooms, RHS 53C outer and 53A inner, opening deep and radiant then slowly lightening towards a pinkish tone; petals paler at the edge, retaining impact as they fade. |
| Fragrance and aroma |
Very weak scent with a barely perceptible sweet, fruity note; chosen primarily for continuous colour, health and garden effect rather than for strong fragrance-driven plantings. |
| Hip characteristics |
Usually sparse hip set; occasional small, spherical hips 6–10 mm across in orange-red tones, offering modest late-season interest without significantly affecting flowering performance. |
| Resistance and winter hardiness |
Highly resistant to powdery mildew, black spot and rust; hardy to approximately −26 to −23 °C (RHS H7, Swedish zone 4, USDA 5b), with good heat and drought tolerance once established. |
| Horticultural recommendations |
Suited to beds, hedges, groups and large containers; plant 60–110 cm apart depending on use, in well-drained soil, with low maintenance needs and simple annual pruning to shape. |
DOUBLE KNOCK OUT® offers continuous cherry-red colour, strong disease resistance and an easy, self-cleaning habit on a durable own-root shrub, making it a dependable, low-effort choice you can select with confidence.
