Knock Out roses are ideally suited to the climate of South Carolina because they have been bred to thrive in heat and humidity while resisting the diseases that typically plague roses in those conditions. Knock Out roses are hybrid shrub roses that are self-cleaning and do not require traditional rose pruning, making them very low maintenance. South Carolina is made up of USDA zones 7 and 8 and Knock Out roses need little protection from winter weather conditions and can be pruned in the early spring.
Provide a planting location with full sun exposure and a nutrient-rich but well-drained soil. Amend deficient soil with several pounds of well-aged manure and or compost at planting time or with once-a-year top-dressings.
Water your Knock Out roses regularly to keep the soil evenly moist but not soaking wet. Weekly deep waterings should be sufficient most of the year in South Carolina, with more irrigation needed in the heat of summer and less when rains are abundant.
Feed your Knock Out roses at least twice a year in the early spring and early summer with an organic rose food such as rose tone or fish emulsion following label dosing directions. A third feeding in late summer or early fall will keep your Knock Out roses blooming well until the first hard frost hits South Carolina in the late fall or early winter.
Mulch around the drip line of the rose each fall with at least a 2-inch-thick blanket of organic mulch such as shredded bark, cocoa bean hulls, compost or leaf mold. Mulch will hold in moisture and keep competitive weeds from cropping up.
Prune your Knock Out rose in the early spring each year after the last hard frost. Shear down the entire shrub to as low as just 2 feet above the crown of the rose. Remove any dead or damaged canes down to the crown. Lift all clippings and debris from beneath the shrub to keep the soil clear before feeding, watering and top-dressing or mulching.