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.Continue Reading
Double knockout roses work well as individual plants or hedges, growing up to 4 feet tall and 3 to 4 feet wide. They need at least 6 hours of sunlight a day. The fall before you plant, test the soil pH level with a kit. The perfect pH level for double knockout roses is 6 to 6.5. Add lime if the soil is too acidic or sulfur if the soil is too basic.
If you have multiple bushes, plant them 3 to 4 feet apart. Loosen the soil around the planting area about a foot deep, working in some manure or compost to aid drainage. Dig the holes so the plants are at the same height as in the containers.
Turn the plant upside down and tap or shake the pot to free the bush. Gently spread the roots and place the plant in the hole. Add soil underneath if the plant is too deep. When you re-fill the hole with soil, tap it down with your hands.
When you have finished planting the double knockout roses, water them thoroughly. Add a few inches of mulch around the base of the plants to control weeds and retain moisture.