All winter I have said, wait to prune your roses. April 15 is time to prune roses. While there are general rose pruning principles, the different types of roses: hybrid teas, floribundas, shrub, climbers, ramblers and miniatures, all have special requirements. The first reason to prune is to remove dead, dying, damaged or diseased wood. The second goal is to shape the plant with an open center. A third goal is to increase air circulation within the plant to reduce potential disease problems and the final objective is to increase flower production.
Any time you prune, you want clean, sharp tools. Since roses are disease prone, disinfect your tools often. I do it between each cut. Some people dip their tools in a bleach and water solution, but that rusts the metal. I prefer keeping a spray bottle of isopropyl (rubbing) alcohol on hand whenever I am pruning.
Pruning cuts on roses are made at a 45-degree angle, about 1/4-inch above an outward-facing bud with the cut slanting away from the bud. As I mentioned, on any type of rose, first remove the dead, blackened, shriveled canes damaged by winter weather. After making each cut, seal the end of the cut with white glue to prevent borers from drilling down into the cane and killing it.
Hybrid teas, floribundas or miniature roses produce flowers on new wood, so to encourage that new wood, they require extensive early spring pruning. Reduce their height by one-third to one-half. Leave about five healthy large canes evenly spaced around the plant. Leave five to seven outward-facing buds on each cane.
Shrub roses are repeat flowering and bloom best on mature wood, as long as it isn’t too old or too woody. Other than removing dead or damaged parts, these roses aren’t pruned for the first two or three years after planting. Even then, they require little pruning other than to shape them by removing one-quarter to one-third of the oldest canes.
Climbers and rambling roses are similar to shrub roses in that they too need little pruning their first few seasons, other than the removal of damaged wood. Climbers, being repeat bloomers, are pruned now, while ramblers, since they only bloom once, are pruned in early summer right after they have flowered. The new growth that develops on ramblers after pruning will bear flowers the following year. Training canes to grow horizontally on either of these types will stimulate side shoot development and more flowers.
JoAnne Skelly is Associate Professor & Extension Educator, Emerita at University of Nevada Cooperative Extension. She can be reached at skellyj@unce.unr.edu.