Knockout roses bring a punch to landscapes | Home & Garden

By Gary R. Bachman

MSU Horticulturist
Coastal Research & Extension Center

A lot of new gardeners who enjoy roses want to jump right into growing hybrid tea or floribunda roses, but these can be tricky for beginning gardeners. I think the easiest way for the gardening novice -- or the master gardener -- to enjoy roses is to plant Knockout roses.

Knockout roses are very disease-resistant, shrub-type roses. They produce flower clusters nonstop and in huge numbers. Colors range from red to pink and yellow, and flowers can be 3 1/2 inches in diameter.

This plant has multi-season interest. The foliage in the spring and summer is a dark, glossy green, and fall brings on a deep maroon-purple show.

Choose a location that receives at least five hours of full sun a day. Morning sun is most beneficial. Incorporate good organic matter into the landscape bed, and raise the bed above the normal grade to improve drainage around the plant crown. Avoid overhead watering if possible, and use drip irrigation or soaker hoses to keep the soil moisture consistent.

The plants can easily grow 3 to 4 feet tall and wide if unpruned, but pruning helps you enjoy the full landscape potential of Knockout roses.

Pruning roses is actually very easy; it may be harder to convince yourself that pruning is necessary! An overgrown Knockout rose bush is not very attractive, so get out the pruners and get started.

Always protect yourself when pruning roses. Wear heavy-duty leather gloves and long sleeves to keep pesky thorns at bay.

Always use bypass pruners, because these produce the best and cleanest cut, like a pair of scissors cutting paper. Anvil pruners, while less expensive, do a great deal of damage by literally crushing the rose stems. Crushed stems are not attractive and can allow disease organisms into the plant.

Prune Knockout roses early each spring. The first step is removing any dead or winter-damaged canes by cutting them off close to the base of the plant. Prune the remaining canes up to 50 percent, maintaining the desired shape and size of the shrub as you prune. Cut the canes at a 45 degree angle facing out to prevent the canes from holding water.

Pruning will stimulate vigorous growth in the spring and the abundant flowering Knockouts are known for.

Later this summer when the rose bushes are starting to look a little tired, prune them back by about a third. The resulting flush of growth will produce a display of flowers to enjoy in the fall.