Knock Out roses, hardy shrub roses first introduced to the market in 2000, produce medium-sized, single blossoms in shades of red and pink, depending on variety. The plant's thorny canes produce dark-green leaves that turn reddish-purple in autumn. Later in the season, the plants produce orange-red rose hips that add interest during the winter months. Winner of the All American Rose Selection award for outstanding garden performance, Knock Out roses require little maintenance, tolerate heat and drought, and resist most pests and diseases. Hardy in USDA hardiness zones 4 through 9, Knock Out roses thrive in most areas of the country and bloom abundantly from spring through fall.
Choose a planting location for Knock Out roses that receives full sunlight to light afternoon shade. Cover the ground at the site with a 2-to-4-inch layer of organic compost, and use a garden tiller to cultivate the soil to a depth of at least 6 inches. Space Knock Out roses 8 feet apart to allow room for their mature size.
Spread a 3-inch layer of mulch over the ground around the plant to improve the soil's moisture retention. Provide at least 3 inches of space between the mulch and the base of the Knock Out roses to allow air circulation and reduce disease vulnerability.
Water once every four to five days during the first month of growth to establish the plant. Reduce frequency thereafter to once every week to keep the soil consistently moist. Further reduce watering during winter to once every 10 days. Soak the soil to a depth of 6 to 8 inches at each application.
Feed Knock Out roses once a month during spring and summer to boost rapid growth and flower formation. Apply a balanced 10-10-10 NPK fertilizer according to the product label for the best results. Water the soil lightly prior to fertilizing to reduce the chance of root burn.
Prune the plants using hedge clippers during early spring, just before new growth begins, removing any dead or diseased growth. Cut back any overgrown limbs any time throughout the growing season to maintain an attractive, bushy growth habit.