Rosa 'Radrazz' KNOCK OUT

Tried and Trouble-free Recommended by 10 Professionals
Common Name: shrub rose
Type: Deciduous shrub
Family: Rosaceae
Zone: 5 to 9
Height: 3.00 to 4.00 feet
Spread: 3.00 to 4.00 feet
Bloom Time: June to frost
Bloom Description: Cherry red
Sun: Full sun to part shade
Water: Medium
Maintenance: Medium
Suggested Use: Hedge
Flower: Showy, Fragrant
Leaf: Good Fall
Attracts: Butterflies
Fruit: Showy
Other: Thorns
Tolerate: Air Pollution

Culture

Grow in medium moisture, slightly acidic, well-drained garden loams in full sun to part shade. Unlike most roses, KNOCK OUT will grow very well in part shade locations with excellent disease resistance. Water deeply and regularly (mornings are best). Avoid overhead watering. Good air circulation promotes vigorous and healthy growth and helps control foliar diseases. Summer mulch helps retain moisture, keeps roots cool and discourages weeds. Remove spent flowers to encourage rebloom. Crowns may need winter protection in cold winter areas such as St. Louis. Remove and destroy diseased leaves from plants, as practicable, and clean up and destroy dead leaves from the ground around the plants both during the growing season and as part of a thorough cleanup during winter (dormant season). Prune as needed in late winter to early spring.

Noteworthy Characteristics

KNOCK OUT is a compact shrub rose that typically grows to 3-4’ tall and as wide. It is best noted for its ability to bloom in as little as 3 hours per day of direct sun with excellent disease resistance. Features single, lightly fragrant, cherry-red roses to 3.5” diameter that bloom in clusters from May to frost. Flowers are followed by orange-red hips. Foliage is dark purplish-green in summer, turning purple to burgundy in fall. 2000 AARS winner.

Problems

Roses are susceptible to a large number of diseases, the most common of which are black spot, powdery mildew and rust. Although good cultural practices are the first line of defense in disease control, regular preventative fungicide applications throughout the growing season are often required, particularly in humid climates with regular rainfall such as the St. Louis area. It should be noted, however, that KNOCK OUT has excellent resistance to the aforementioned diseases, and often does not need regular fungicide treatments. Potential insect problems include aphids, beetles, borers, scale, thrips, rose midges, leafhoppers and spider mites.

Garden Uses

This rose grows well as a specimen or in small groups in borders, cottage gardens, foundations or rose gardens. Also effective as a hedge. Excellent selection for part shade locations.