Images Depict Mature Plants
White Knock Out® Rose
Rosa 'Radwhite
White Knock Out® is the rose I would use when someone wants that easy Knock Out® performance but needs a cleaner, softer color in the landscape. The white flowers look sharp against the very dark foliage, and that contrast makes it easy to pair with evergreens, grasses, lavender, catmint, or purple perennials. Give it sun, airflow, base watering, and one good spring prune. It is still a rose, so I would watch for rose rosette and pests, but for a white flowering shrub rose that works hard in real landscapes, this is a strong choice.
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White Knock Out® Rose Delivers Clean White Blooms and Easy Landscape Color
Bright White Roses With Dark Foliage Contrast
White Knock Out® Rose is a compact landscape shrub rose with bright white flowers, very dark green foliage, and repeat bloom from spring into fall. The contrast between the clean white blooms and the deep foliage gives this rose a crisp, polished look in sunny borders, foundation beds, mailbox plantings, and front-yard landscapes.
This rose is especially useful when you want the flower power of a Knock Out® rose but prefer a softer, cleaner color than red, coral, peach, or pink. The white blooms pair beautifully with evergreens, boxwood, lavender, catmint, ornamental grasses, blue salvia, purple coneflowers, black-eyed Susans, and other sun-loving perennials.
A Repeat-Blooming White Rose for Long-Season Color
White Knock Out® Rose blooms repeatedly from spring to frost, providing the landscape with steady color throughout the season. The flowers are single, five-petal blooms with a light floral scent, making them simple, fresh, and easy to blend into both formal and relaxed garden designs.
Because Knock Out® roses are self-cleaning, they do not require constant deadheading to keep flowering. Removing faded blooms can make the plant look tidier, but the rose will continue its natural repeat-bloom cycle without the high-maintenance routine associated with many traditional roses.
Compact Shrub Rose Habit for Hedges, Beds, and Borders
White Knock Out® Rose typically grows about 3 to 3.5 feet tall and wide, forming a compact, bushy shrub that is easy to place in the landscape. Its rounded form works well as a single specimen, a repeat-border plant, a low-flowering hedge, or a mass planting in sunny garden beds.
Use White Knock Out® where you want a rose that reads like a tidy landscape shrub rather than a fussy rose garden plant. It is a strong fit along walkways, fences, patios, driveways, mailbox beds, and foundation plantings where repeat color and a manageable mature size matter.
Disease Resistance With Smart Rose Care
White Knock Out® Rose is bred for strong disease resistance and easier care than many traditional roses. It is especially valued for its resistance to black spot, which helps keep foliage cleaner when grown in good conditions.
That said, no rose is completely problem-proof. Give White Knock Out® plenty of sun, good airflow, and well-drained soil. Water at the base rather than over the leaves, avoid crowding, and remove fallen or diseased foliage when needed. Healthy placement is what helps this rose perform at its best.
Easy Maintenance for Everyday Landscapes
White Knock Out® Rose is simple to maintain with one good annual pruning in late winter or early spring. Cutting the plant back as new growth begins helps refresh the shrub, encourages strong flowering stems, and keeps the plant at a useful landscape size.
Plant it in full sun for the heaviest bloom. Water regularly while it establishes, fertilize after the first bloom cycle if needed, and avoid late-summer feeding so the plant can prepare for dormancy. With those basics, White Knock Out® Rose becomes a dependable white-flowering shrub for homeowners who want roses without a complicated care routine.
| Hardiness Zone: | 4-11 |
|---|---|
| Mature Height: | 3 to 3.5 Feet |
| Mature Width: | 3 to 3.5 Feet |
| Sunlight: | Full sun; 6 to 8 hours of direct sun supports best flowering |
| Soil Condition: | Average, well-drained soil; prefers balanced soil that is not extremely acidic or alkaline |
| Water Requirements: | Water regularly until established; water deeply during drought |
| Bloom Time / Color: | Spring to frost; white flowers |
| Foliage | Very dark matte green foliage; young foliage may appear almost black |
| Ornamental Features | White repeat blooms, dark foliage contrast, compact habit, light fragrance, long bloom season, easy-care landscape rose performance |
| Wildlife Value: | Flowers may attract pollinators |
| Resistance: | Strong disease resistance, especially black spot resistance; drought tolerant once established; not deer resistant |
| Landscape Uses: | Foundations, flowering hedges, borders, mass plantings, mailbox beds, driveway edges, sunny walkways, patio borders, curb appeal plantings |
How to Care for White Knock Out® Rose
Be sure to read our planting instructions to ensure a healthy and happy White Knock Out® Rose plant for years to come!
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How should I plant White Knock Out® Rose?
Plant White Knock Out® Rose in full sun with well-drained soil. Choose a spot with 6 to 8 hours of direct sun each day for the strongest flowering and healthiest growth. Avoid low, soggy areas, deep shade, or crowded locations with poor airflow. Dig a hole slightly wider than the root ball and loosen the soil at the bottom and sides of the hole. Set the rose so the base of the plant is level with the surrounding soil, backfill with loosened native soil, water deeply, and apply mulch around the root zone while keeping mulch away from the crown and main stems.
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How often should I water White Knock Out® Rose after planting?
Water White Knock Out® Rose deeply after planting and keep the root zone evenly moist while the plant establishes. During the first few weeks, check the soil regularly and water when the top few inches begin to dry. Deep watering is better than frequent shallow watering. Once established, White Knock Out® Rose can handle normal garden conditions but will bloom better with supplemental water during extended dry periods. Water at the base of the plant instead of overhead to help keep foliage drier and reduce fungal disease pressure.
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When should I fertilize White Knock Out® Rose?
White Knock Out® Rose can perform well without heavy feeding, but fertilizer can help support stronger growth and bloom. Wait until the plant is established and has gone through one bloom cycle before fertilizing. Then use a balanced fertilizer or rose fertilizer according to the label. Make sure the soil is moist before applying fertilizer to avoid root burn. Do not fertilize late in summer because the plant should begin preparing for dormancy instead of pushing tender new growth that may be damaged by frost.
When and how should I prune / cut back White Knock Out® Rose?
Prune White Knock Out® Rose in late winter or early spring when you begin to see new shoots emerging from the canes. For a compact 3- to 4-foot shrub, Knock Out® roses are often cut back to about 12 inches once per year. After the main cutback, remove small, weak, damaged, dead, crossing, or crowded canes to improve airflow and encourage stronger growth. Wear gloves, use clean sharp pruners or hedge shears, and discard pruning debris rather than leaving it around the plant.
