Care of Knock Out Roses
- Knock Out roses thrive in most soils as long as they are well drained and not prone to standing water. Working a 2- to 3-inch layer of compost into the soil helps improve the quality and drainage of the bed before you plant a new rose bush. Choose a site where the bush will receive six to eight hours of daily sunlight, since the roses bloom best when provided with plenty of light. Avoid overcrowding the bushes. A Knock Out rose bush reaches up to 5 feet wide. Space plants 6 to 8 feet apart so they don't become crowded and to allow sufficient air circulation around the plants.
- Water once a week in spring, summer and fall. The roses require only minimal irrigation in winter when the plants are dormant. Provide enough water to moisten the top 10 to 12 inches of soil around the base of the Knock Out bush. Mulch helps retain the moisture in the soil and keeps the rose's roots cool. Apply the mulch in a 3-inch-deep layer over the soil. Leave a space between the mulch and the trunk of the Knock Out bush, since the moisture in the mulch can cause the trunk of the rose to rot if they are in direct contact.
- Fertilize your Knock Out rose bushes twice a year. Provide the first application in early spring when new growth begins. Apply 2 lbs. of a slow-release rose fertilizer per 1,000-square-foot bed. Fertilize a second time in late summer, applying just a pound of fertilizer per 1,000 square feet. Apply the fertilizer 6 to 8 inches out from the trunk of the rose bush. Damage can occur when undiluted fertilizer comes in contact with trunks, roots and foliage.
- Knock Out roses require only minimal pruning. Prune every two to three years, removing up to a third of the plant's height and thinning the interior branches to allow air flow. Prune in late winter while the rose is still dormant. In areas that experience minimal winter frost, you can prune in late summer instead. Knock Out roses do not require deadheading since they drop wilted flowers on their own.
