‘Pink Double Knockout’ roses at UT Gardens in Knoxville, TN

Knockout® roses continue to wow gardeners across the U.S. (USDA hardiness zones 5 to 9). The original Knock Out series grew 5 to 8 feet tall and 4 to 6 feet wide. Shorter growing Double Knockout® series make better fit in most urban gardens at 3 to 4 feet high and 3 to 4 feet wide. Double blossoms have the look of hybrid tea or floribunda roses. Colors range from red, pink, coral, and yellow.

All Double Knockout roses are bred for its resistance to common rose pests and diseases. They bloom heaviest in May and June, retreating in the heat of summer and finish with a flurry of color in late summer and fall. They hold up under rough weather and moderate drought.

Roses are best planted from spring thru mid-summer to permit roots adequate time to grow deeply before winter arrives. Double Knockout® roses should be planted 4 feet apart in a garden site that receives 6 to 8 hours of sun most days and in well-drained soil that ranges between pH 6.0 and pH 6.5. Roses need good air movement, so don’t crowd them.

Dig a wide hole to accommodate the roots from the container grown plant. Set the root ball slightly shallow in the hole. Backfill the hole with soil and water deeply. After planting, water regularly (usually weekly) until the plant becomes well established. Apply 2-3 inch depth of an organic mulch to conserve soil moisture and reduce weed infestation. Do not pile mulch around the rose trunk.

Fertilize Double Knockouts with a water-soluble fertilizer monthly from early spring until September 15 (no later). An alternate feeding method is to use special organic based rose foods sold at most garden centers.

In late winter or early spring prune roses when they are still dormant to remove all dead or damaged wood and to maintain the roses at a desired size.