Knockout roses are flowering bushes that produce large, bright flowers. The fragrance produced is not as strong as other varieties of roses, and the flowers do not typically last as long after being cut. However, the knockout rose is exceptionally easy to care for, and is resistant to drought and many diseases. The flowers can be pink, red or yellow, and will bloom throughout most of the year in warm climates.
Plant knockout roses in a location that receives between six and eight hours of direct sunlight each day. Ensure the soil is fertile and has high drainage; additional organic compost can be added if necessary. Plant the roses in late April, after the last frost of the season and when the soil has warmed to a workable temperature.
Dig a hole 2 feet wide by 2 feet deep to plant each knockout rose. Transplant the bush directly into the hole and cover with soil. Water thoroughly after planting to compact the soil and collapse any air pockets.
Water the knockout roses two to three times a week until they become established. This will promote root growth, and help the plant create more food for developing leaves and blossoms. Reduce watering to about 1 inch per week after the first three months. Never allow the leaves to get wet, as this can cause disease. Water the roses as early in the day as possible, so any leaves that do become moist will dry out before the temperature drops in the evening.
Mulching and Fertilizing
Spread a 2- to 3-inch layer of mulch directly around the base of the knockout roses. This will help conserve water, maintain a constant soil temperature, add additional nutrients to the soil and discourage the growth of weeds. Replace the mulch after two or three months, or when it is visibly deteriorating.
Feed the knockout roses with a balanced fertilizer with 10-10-10 NPK or similar. Spread between ½ and 1 cup of fertilizer directly around the base of the plants in late April. Continue feeding every four to five weeks until late August. Prevent root burn by watering the roses before and after applying the fertilizer.
Prune knockout roses once yearly in late March. Remove any stems that are dead, dying or diseased. Cut back all other stems to a length between one and two feet. This will provide more air circulation and light to penetrate to the inner portions of the bush, reducing the chance of fungi or diseases.