Knockout roses are almost a "stand alone rose," meaning they take no special care and can be planted and left. However, some special care can be taken to ensure great looking flowers.
To plant knockout roses, select a sunny location that receives at least six hours of sunlight a day. Dig a large hole, wider than the root ball, and insert the plant.
Grow a Knock Out rose bush by planting it in a location with well-drained soil and full sun, watering it regularly, fertilizing it, and pruning it in the early spring, Today's Homeowner suggests. This plant is naturally disease resistant and low maintenance.
To trim Knock Out roses, prune them during the second season of growth, trim them vigorously in late winter, and then shape the bush during the growing season. Remove dead or diseased wood, and cut away limbs that rub together. You need pruning shears or hedge clippers.
Knockout roses should be pruned just as buds break dormancy. The perfect time to prune is when buds have swelled, but not yet shown leaves. This can be anywhere from February to May, depending on your U.S. Department of Agriculture growing zone.
Double knockout roses are self-cleaning and bloom every 5 to 6 weeks. Plant them in early spring. You need a soil test kit, lime or sulfur, the rose plants, a shovel, manure or compost, and mulch.
According to SF Gate, knockout roses should be fertilized every four to six weeks after the first bloom. However, knockout roses generally do not require fertilizer for the first year after they are planted.