How to Grow Double Red Knock Out
Double Red Knock Out
Rosa 'Double Red Knock Out'
shrubDouble Red Knock Out is a modern shrub rose known for its vibrant red double flowers and exceptional disease resistance. It blooms continuously from spring through fall with minimal maintenance, making it one of the most reliable landscape roses available. This hardy, compact shrub typically grows 3-4 feet tall and wide.
When should you plant Double Red Knock Out in your zone?
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Example Double Red Knock Out timeline · Pittsburgh, PA (Zone 6b)
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Plant Double Red Knock Out
Around Apr 17Near Pittsburgh's average last spring frost.
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Tend & protect
Late spring–summerWatering, feeding, and pest-watch reminders.
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Harvest Double Red Knock Out
Around Apr 18≈ 1 days after planting
Sample dates for Pittsburgh, PA. Sign up to get exact Double Red Knock Out dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in zones 4-9, with best performance in zones 5-8
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Establishment
4-8 weeksNew transplant with initial growth of lateral shoots and root system development
Water deeply and frequently. Mulch around base. Prune lightly to shape. Avoid fertilizing first 4-6 weeks.
Vegetative Growth
6-10 weeksRapid shoot and leaf development with dense foliage formation
Water consistently. Begin regular feeding schedule every 4-6 weeks. Remove any diseased foliage immediately. Monitor for pests.
First Flowering
3-4 weeksInitial blooms appear, typically smaller than subsequent flushes, with flower clusters at shoot tips
Deadhead spent flowers to encourage more blooms. Continue regular watering and feeding. Maintain consistent care schedule.
Continuous Blooming
Spring through fall (4-6 months)Abundant double red flowers produced in waves throughout growing season, with prominent stamens visible in some blooms
Deadhead regularly for maximum bloom production. Water during dry periods. Feed every 4-6 weeks until late summer. Reduce watering slightly in fall.
Dormancy
2-3 months depending on climateLeaf drop and growth cessation in winter as plant enters rest period
Cease fertilizing in late summer/early fall. Reduce watering in dormant period. Prune in late winter/early spring before growth resumes.
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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Hand-pick early morning, use pheromone traps away from rose, apply insecticidal soap, encourage parasitic wasps
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Increase humidity with regular water misting, spray with insecticidal soap or neem oil, avoid overhead watering to prevent spread
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Spray with strong water stream, use insecticidal soap, neem oil, or systemic insecticide; encourage beneficial insects
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Remove and destroy infected plant immediately to prevent spread; maintain rose health to prevent infection
Uses
Rose Petals for Tea & Edibles
CulinaryPesticide-free petals can be used fresh or dried for herbal teas, infusions, and as edible garnishes for desserts and cocktails. Rose petals add a delicate floral flavor and aroma to culinary preparations. [source]
Cut Flowers & Arrangements
HouseholdExcellent choice for fresh flower arrangements and bouquets with long vase life (up to 2 weeks). The continuous blooming nature means fresh flowers are readily available throughout the growing season. [source]
Rosehip Benefits
MedicinalWhile Double Red Knock Out produces minimal hips compared to species roses, any hips formed are rich in vitamin C and can be used for teas, syrups, and supplements supporting immune health. [source]
Dried Flowers & Potpourri
CraftFlowers can be dried for use in potpourri, dried arrangements, floral crafts, and botanical decorations that retain their color and fragrance for extended periods. [source]
Pollinator Support
WildlifeProvides nectar and pollen for bees, hoverflies, and other beneficial insects throughout the blooming season, supporting pollinator populations in the garden. [source]
This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.
Harvest Tips
For cut flowers, harvest in early morning or late evening when stems are fully hydrated. Cut at 45-degree angle just above an outward-facing leaf set. Use sharp pruning shears. Place immediately in cool water with floral preservative. Deadhead spent flowers regularly throughout growing season to promote continuous blooming; remove entire flower cluster rather than individual blooms.
Fun Facts
- 🌱 Double Red Knock Out was developed by Will Radler and is the red form of the original Knock Out rose, which revolutionized home gardening by being one of the first roses requiring minimal deadheading and disease management.
- 🌱 It is nearly immune to black spot and powdery mildew due to its hybrid parentage and breeding for disease resistance, making it an excellent choice for gardeners in humid climates where these diseases are common.
- 🌱 The name 'Knock Out' refers to how the rose 'knocks out' the competition in the garden—it blooms continuously without the demanding care requirements of traditional hybrid tea roses.
Gardening Terms
New to gardening? Learn about terms used in this guide:
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