Knockout Rose
Rosa Radrazz
Disease-resistant rose that blooms continuously from spring to frost.
Care Instructions
Water at the base (not on foliage) once or twice a week. Allow the top inch of soil to dry between waterings. Mulch 2–3 inches around the base to retain moisture.
Requires at least 6 hours of direct sun daily. More sun = more blooms. Avoid locations with only morning shade.
Rich, well-drained loam with pH 6.0–6.5. Incorporate compost at planting. Fertilize monthly spring through summer with a rose-specific fertilizer.
Seasonal Guide
Best Planting Time
Spring after last frost or fall 6 weeks before first frost. Container-grown plants can go in almost any season.
Bloom / Growth Season
Blooms continuously from late April through first hard frost. Deadheading is not required but light shearing encourages fresh flushes.
Dormancy
Semi-dormant in winter in zones 4–6. Prune back by one-third in early spring when forsythia blooms.
Common Problems & Solutions
Black spot (dark leaf spots)
Knockout Roses are resistant but not immune. Remove affected leaves, improve air circulation, and apply neem oil spray.
Japanese beetle defoliation
Hand-pick in early morning and drop into soapy water. Apply pyrethrin spray for heavy infestations.
Rose rosette disease (red, distorted growth)
No cure. Remove and destroy the entire plant immediately to prevent spread to neighbors.
Plant Details
USDA Zones
4a, 4b, 5a, 5b +8
Maintenance
low
Mature Height
3-4 ft
Native Regions
Hybrid
Ready to plant?
Find Knockout Rose and related supplies on Amazon.
As an Amazon Associate, YardSage earns from qualifying purchases. This helps us keep the app free.
Similar Plants
Eastern Redbud
Cercis canadensis
Stunning spring bloomer with magenta-pink flowers that appear before leaves.
Black-Eyed Susan
Rudbeckia hirta
Native wildflower with bright yellow petals and dark centers.
Bermuda Grass
Cynodon dactylon
Tough warm-season grass ideal for hot, sunny yards.