Methods and practices for pruning established roses vary with different rose types. In general, the object is to remove all dead or diseased wood, and old, weak or undesirable wood, as well as to shape the plant.
In most areas of Colorado, a substantial portion of the canes of hybrid teas, grandifloras and, to a lesser extent, floribundas and polyanthas are damaged by the winter climate. Pruning is easier if only the dead portion of these canes is removed in early spring. Close or low pruning of the canes usually stimulates new growth. If pruned too early, this new growth may be severely damaged or killed by late frost. Delay close or low pruning at least until two weeks before the last killing spring frost. For healthy growth, cut the canes back to live wood. A live cane has a white center and green inner bark. Prune to produce an open center and to shape the plant. After a severe winter, only a few inches of healthy cane may be left on hybrid teas and grandifloras.
Miniature roses are very hardy, and pruning usually consists of removing dead and damaged wood and thinning and shaping the plant. Pruning floribundas and polyanthas is similar to miniatures, but there usually is more dead wood to remove.
Prune climbers to remove dead wood and old, unproductive canes. Prune shrub roses to remove dead wood, damaged canes and weak, twiggy growth. Wait until immediately after the June bloom to remove old canes to thin and rejuvenate shrub roses, climbing hybrid teas and climbing grandifloras.
All canes should be pruned at a 30- to 45-degree angle above a live leaf, leaving no more than 1/4-inch of stub above the leaf. Remove any dying or dead stubs throughout the year to discourage the carpenter bee, a small pith borer that nests in tunnels bored into rose canes. If this insect is a serious problem, seal the ends of the pruned canes with a substance, such as common white glue, that discourages the bee from boring a hold down the center of the canes.
For additional information read, Roses: basics
