Q How do I prune and take care of Double Knock Out roses?
A Knock Out roses have become wildly popular in recent years for several very good reasons.
The plants are tough and resistant to disease (though not totally disease-free). They have a pleasant bush-type shape. They are easy to establish and grow. They produce blooms all summer with a minimal amount of attention. In short, they are about as easy as roses can get.
You can allow Knock Outs to grow tall or keep them shorter and shrubby. You can even cut tall ones back sharply, and they will branch out and grow.
These are shrub roses, not hybrid teas. In general, you should plan on pruning shrub roses in late winter or early spring. Usually, we are advised to trim back one-third of the foliage in late winter.
For the health of the plants, you can cut out interior branches so that light and air can penetrate the plant to fight off fungus problems. They can be cleaned up in the fall to neaten them, but leave enough stems and branches so that you can trim any damaged areas in spring. Roses can sustain winter damage from the burning and drying of cold winter winds.
In spring, remove any damaged wood and clip back dried stems. Fertilize plants with a good rose food. Allow them to bloom, then trim them to your desired shape and height. Fertilize again, and new foliage and blooms will result in a heavy second round of flowers. Deadhead spent blooms and fertilize every other week, and you should have lots of continuing blooms all summer.
Email Pat Lea at firstname.lastname@example.org.