HybridContainer OK

Knock Out Rose

Rosa 'Radrazz'

The revolutionary rose that changed home gardening forever with its exceptional disease resistance and continuous blooming from spring to frost. This low-maintenance beauty produces clusters of bright cherry-red flowers without the fuss of traditional roses, making it perfect for busy gardeners who want stunning color all season long.

Sun

White-Tailed Deer

☀️

Zones

5–11

USDA hardiness

🗺️

Height

1-8 feet

📏

Planting Timeline

Zone:

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Transplant

Showing dates for Knock Out Rose in USDA Zone 7

All Zone 7 rose →

Zone Map

Click a state to update dates

Knock Out Rose · Zones 5–11

What grows well in Zone 7? →

Growing Details

Difficulty

Easy

Spacing4-6 feet

SoilWell-drained, fertile soil with organic matter

pH6.0-7.0

Water1 inch per week, drought tolerant once established

SeasonPerennial, blooms spring through fall

FlavorN/A - Ornamental use only

ColorBright cherry-red

Size3-4 inch flower clusters

Zone-by-Zone Planting Calendar

Zone	Indoor Start	Transplant	Direct Sow	Harvest
Zone 5	—	May – July	—	—
Zone 6	—	May – July	—	—
Zone 7	—	May – June	—	—
Zone 8	—	April – June	—	—
Zone 9	—	March – May	—	—
Zone 10	—	March – April	—	—

Complete Growing Guide

Light: White-Tailed Deer, Cottontail Rabbit. Soil: Clay, Loam (Silt). Soil pH: Acid (<6.0), Neutral (6.0-8.0). Height: 1 ft. 0 in. - 8 ft. 0 in.. Spread: 1 ft. 0 in. - 6 ft. 0 in.. Spacing: Less than 12 inches, 12 inches-3 feet, 3 feet-6 feet, 6-feet-12 feet. Growth rate: Medium. Propagation: Grafting.

Harvesting

The accessory fruit is called a hip and forms after the flowers finish blooming. The hip will appear under the sepals of where the flower was after the flower dies. They will turn from green to red. They are filled with many achenes surrounded by irritating hairs.

Color: Green, Red/Burgundy. Type: Achene. Length: < 1 inch. Width: < 1 inch.

Garden value: Showy

Harvest time: Fall

Bloom time: Summer

Edibility: The fruit (called the hip) is edible.

Storage & Preservation

Fresh cut Knock Out rose stems last longest when immediately placed in lukewarm water, then moved to cool water with flower preservative. Recut stems underwater every 2-3 days and change water completely. Store arrangements away from direct sunlight and heat sources - they'll maintain quality for 5-7 days.

For preservation, hang small bouquets upside down in a dark, dry, well-ventilated area for 2-3 weeks until completely dried. Dried roses retain color best when picked just before full bloom. You can also press individual petals between paper in heavy books for 4-6 weeks.

Rose hips can be dried whole for winter arrangements or crafts. Spread fresh hips on screens in a single layer, turning daily until completely dry (usually 10-14 days). Store dried hips in airtight containers away from light. Fresh hips also freeze well whole in freezer bags for up to one year and can be used later for wildlife feeding or decorative purposes.

History & Origin

Origin: Temp. & Subtropical Northern Hemisphere (such as Europe & Asia)

Advantages

+Disease resistance: #showy flowers#fragrant flowers#heat tolerant#rose#tsc#cottage garden#security plant#high maintenance#English garden#cutting garden#border back#tsc-s#bee friendly#container plant#patio#hedge#prickles#shrub rose#cpp#walkway#HS111#HS303#hortcontest#nesting site#fpp
+Wildlife value: Wildlife is attracted to the edible hips. Single-flowered species and cultivars are attractive to bees. Dead stems are used by stem-nesting bees.
+Edible: The fruit (called the hip) is edible.

Companion Plants

Plant Together

Lavender

Repels aphids, spider mites, and other rose pests while attracting beneficial pollinators

Marigold

Deters nematodes, aphids, and whiteflies with natural compounds

Garlic

Repels aphids, thrips, and Japanese beetles while improving soil health

Catmint

Strong scent deters ants, aphids, and rodents while attracting beneficial insects

Allium

Sulfur compounds repel aphids, thrips, and other soft-bodied insects

Parsley

Attracts hoverflies and other beneficial insects that prey on rose pests

Clematis

Complementary root systems and provides vertical interest without competing

Chives

Natural fungicide properties help prevent black spot and powdery mildew

Keep Apart

Black Walnut

Produces juglone toxin that inhibits rose growth and can cause wilting

Large Trees

Compete for nutrients and water while creating excessive shade roses cannot tolerate

Fennel

Allelopathic properties inhibit growth and development of roses

Pests & Disease Resistance

Resistance

Exceptional resistance to black spot, powdery mildew, and downy mildew

Common Pests

Japanese beetles, aphids, spider mites, thrips

Diseases

Generally disease resistant, occasional canker or rust in humid conditions

Frequently Asked Questions

How big do Knock Out roses get?▼

Knock Out roses typically reach 3-4 feet tall and wide at maturity, though they can grow up to 5 feet in ideal conditions. Their rounded, bushy growth habit makes them perfect for foundation plantings, borders, or mass plantings. Annual pruning in late winter helps maintain desired size and shape, and you can keep them smaller with more aggressive pruning if needed for tight spaces.

Do Knock Out roses need full sun?▼

Yes, Knock Out roses perform best with 6-8 hours of direct sunlight daily. While they can tolerate partial shade (4-6 hours), you'll see reduced flowering and potentially more disease issues. Morning sun is especially important for drying dew from leaves quickly. In extremely hot climates, some afternoon shade can actually help preserve flower color and extend bloom life.

When should I prune my Knock Out roses?▼

Prune Knock Out roses in late winter while they're dormant, typically February through early March depending on your location. Cut back all canes by one-third to one-half, remove any dead or diseased wood, and open up the center for air circulation. You can also do light pruning in mid-summer if plants become too large, but avoid heavy pruning after August as it can stimulate tender growth vulnerable to frost.

Are Knock Out roses deer resistant?▼

Knock Out roses have moderate deer resistance due to their thorny stems, but hungry deer will still browse them, especially new growth and flowers. In areas with high deer pressure, consider using deer repellent sprays, installing fencing, or planting them closer to high-activity areas around your home. The thorns provide more deterrent than many other garden plants, but they're not completely deer-proof.

Can you grow Knock Out roses in containers?▼

Yes, Knock Out roses grow well in large containers at least 18-20 inches wide and deep. Use quality potting mix with good drainage, and expect to water more frequently than ground-planted roses. Container roses need regular fertilizing every 4-6 weeks during growing season. In cold climates, protect containers from freezing by moving to an unheated garage or wrapping with insulation, as roots are more vulnerable to cold damage in pots.

Why are my Knock Out roses not blooming?▼

Poor blooming usually results from insufficient sunlight (less than 6 hours daily), over-fertilizing with nitrogen which promotes foliage over flowers, or stress from drought or poor drainage. Check that your roses receive full morning sun and adequate water during dry spells. Avoid high-nitrogen fertilizers in favor of balanced formulations, and ensure soil drains well but retains some moisture.