Roses can present a challenge to the gardener. They need regular feeding and water. Many roses are also prone to insect problems and mildew. These problems, and the fact that many roses bloom only once a season, keep many gardeners away from them. There are, however, several roses grown for their disease-resistance and their proclivity to bloom from spring to fall. The Knock Out rose is one of the best roses to achieve easy-to-care-for blooms well into autumn.
Knock Out roses were born from the efforts of William Radler, former director of the Boerner Botanical Garden in Minneapolis. Radler was looking for a disease-resistant shrub rose that bloomed from spring through fall. The effort took 20 years and Knock Out became available in 2000, winning the coveted All-America Rose award.
Knock Out is a shrubby rose. It grows 3 feet tall and wide and bears clusters of single, open, cherry-red blooms. The blooms have a light, fresh, tea fragrance. Knock Out blooms consistently from spring to autumn.
Knockout was bred specifically to be resistant to black spot, the chief fungal disease of roses. In addition to black spot-resistance, it is also less vulnerable to other fungal diseases and rarely requires spraying with fungicide.
Knock Out can be used wherever a flowering shrub is called for. It can be planted as a featured plant in the perennial garden. Knock Out is often used as a foundation planting or used to create a flowering hedge. Because it doesn’t require spraying, Knock Out is good for use in a container on a patio or balcony.
Plant Knock Out in full sun. Like other roses, it requires moist, well-drained soil. Water, at ground level, weekly during drought. To keep the rose growing and producing flowers, use a slow-release fertilizer according to label instructions. Trim off spent flower heads. In early spring, cut bushes back by one-third to encourage branching.