The Knock Out rose, a cultivar introduced to the market in 2000, blooms profusely with minimal upkeep, making it one of the most popular and widely sold varieties of rose in North America. In addition to its generous flowering, gardeners also value the Knock Out rose for its tolerance to drought, resistance to disease and self-cleaning habit. The Knock Out rose blooms once every five to six weeks until the first frost and makes an attractive addition to any flower garden. Although the plant's winter appearance is less than desirable, planting behind low, evergreen shrubs remedies the problem.
Plant Knock Out rose plants in a location that receives six to eight hours of direct sunlight each day. Apply a 1-inch layer of compost to the planting site and use a garden tiller to work it into the soil before planting. Space Knock Out roses 3 to 4 feet apart.
Spread a 3-inch layer of organic mulch over the soil surrounding Knock Out roses to suppress weeds and increase moisture conservation. Replenish the mulch as often as necessary to keep it 3 inches thick year round. Allow about 3 inches between the layer of mulch and the base of the roses for air circulation.
Water Knock Out roses once every five days during the first two months of growth to help establish the roots. Reduce the frequency of watering thereafter to once every 10 days. Apply the water directly to the soil instead of watering overhead for the best results.
Feed once per month during the spring, summer and fall seasons. Use a balanced 10-10-10 NPK fertilizer to promote profuse flowering and increase root growth. Apply at the rate specified by the manufacturer's instructions.
Use pruning shears to cut back Knock Out rose plants to about 18 inches in height once each year, starting in the second year of growth. Prune during late winter just before active growth begins in the spring to prevent injuring the plants.