Winter takes its toll on Colorado roses. The canes die back, leaving dead growth to prune in the spring. Untimely pruning can leave roses vulnerable to killing frosts. Wait until two weeks before the last average hard frost to prune. The last average frost date in Denver is May 10.
Pruning varies with different rose types, but plan on cutting back hybrid teas and grandifloras every year.
Remove dead or diseased canes first, and then focus on shape. Always make a 30 to 45-degree cut one-quarter-inch above a live bud with the bud eye pointing outward from the plant.
Prune the cane back one-half-inch into green live wood. In severe winters, there may be only a few inches of green on the canes.
Live wood on older canes or roses with bronze stems may look brown instead of green. Clip from the top down, checking for live growth with each small portion removed. Where possible, prune to an outward facing bud to direct growth away from the center of the plant. This allows light and air penetration, minimizing disease.
Miniatures, floribundas, and polyanthas are hardier plants that don’t always suffer winter damage but check yearly.
Climbing roses have intertwined canes, making them more difficult to prune. You may delay pruning on repeat bloom climbers until after the first flowering to encourage new bloom. Dead wood can be removed at any time.
For more information, see the following Colorado State University Extension fact sheet(s).
For more information, see the following Planttalk Colorado™ script(s).
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Updated Tuesday, October 13, 2015