Wait to prune roses

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By Dennis Morgeson

After the frosts and freezes I have gotten numerous calls on roses particularly knockout roses and when to cut them back.  You wouldn’t believe how many people have knockouts that have overgrown their bounds this year. This means one thing, we had a good year!

Roses and knockouts included should be cut back around Thanksgiving or a little after, generally in Kentucky. We need to have temperatures in the low twenties to burn back rose leaves and send the plants into dormancy. If you cut them back too soon and we have some more “warmer” weather, they can try to regrow and the new shoots will get burned and it causes the plant to be less cold harder because it doesn’t get to harden off properly.

Knockouts are shrub roses and generally with a shrub rose you shouldn’t cut it back more than one third at a time. But, with knockouts they grow so fast and so profusely it is alright to cut them back a little further and even cut them down to 8 or 10 inches every few years just to keep them in check.

Hybrid tea roses or the ones with the long stem and single large flower should be cut back to around 8 inches and then covered with several inches of soil, mulch, or straw to protect the bud union. This is the swollen area at the base of the plant where new shoots arise from. If this freezes out your plant won’t die but will turn wild from growth from the root stock.

Floridbunda roses should only be cut back by about a third if that much. These roses only grow about three feet tall or less and have flowers in clusters  These should also be covered with a protective layer of soil, mulch, or straw.

Climbing roses should not be cut back in the fall if they are attached to a structure. Climbers should be left intact and then only the dead and diseased canes trimmed out in the spring. They should (for the most part) have a layer of protection over the bud union like other roses however.

If you have any questions on roses give me a call at the Washington County Extension Office at 859-336-7741.