Knock Out roses are winter hardy to USDA Planting Zone 5, and heat-tolerant throughout most of the United States. They thrive almost everywhere in the country. These tough plants are well loved not only for their beauty, but for their durability and minimal care requirements as well. But even these sturdy roses do need a little winterization in the regions with cold winters.
Remove any dropped foliage beneath your Knock Out roses following the first hard frost in late fall. This will help keep diseases at bay next year.
Wait until sustained temperatures are under 20 degrees Fahrenheit and most of the plant's leaves have dropped.
Use sharp, clean shears to prune your Knock Out roses back when they've gone completely dormant. Cut out any dead or damaged wood. Clip off long or rangy stems that could be damaged by the weight of snow and ice. Trim them flush with the rest of the plant's foliage.
Apply 3 to 4 inches of straw mulch to protect the base and roots of the rose bushes.