How to Prune Knock Out Roses

Knock Out Roses, prized for their profuse blooming that begins in spring and lasts until the first frost of fall, range in color from yellow to pink and red. These shrub roses grow to a height of 3 to 4 feet and spread to cover 3 feet or more. Two- to 3-inch single or double blooms appear in clusters at the ends of branches. Blooming follows a 5- to 6-week cycle that repeats throughout the year. These hardy roses are disease resistant and make striking landscape roses, but do require some pruning to maintain their overall shape and size.

Difficulty: Easy

Instructions

Things You'll Need:

• Pruning shears

1. Prune in early spring to encourage new growth. Use a sharp pair of pruning shears to remove weak or spindly canes. These canes are generally unproductive and rob the plant of energy that would be used for blooming.

2. Cut all but the strongest and healthiest canes back to the ground level and top the others to a height of 2 feet below the desired height. A 3-foot bush should be cut back to 1 1/2 feet in the spring to maintain the height of 3 feet by the end of summer. Five or six healthy canes are enough to produce a healthy bush. Allowing all canes to grow produces more blooms, but the size and color of the flowers will suffer.

3. Maintain the overall shape of Knock Out Roses by trimming stray or overgrown branches back to the level of other branches throughout the summer. This encourages the plant to send out side shoots and prevents overgrown branches from disrupting the shape of the plant. Although they require little pruning during the growing season, sudden growth may cause some branches to shoot beyond the shape of the plant, disrupting the overall appearance. Deadhead blooms regularly to encourage the plant to produce more blooms.

Tips & Warnings

• Avoid heavy pruning in the fall, as this may weaken the canes and they may not survive the winter, particularly if exposed to harsh winds.