Q: When do I prune shrub roses? Is now okay? How far back do I cut?
A: Although you probably won’t kill a plant by doing it now (November) it’s best to wait until late winter or early spring (late February to early March time frame for central Maryland). Pruning before the dormant season might reduce some winter hardiness, potentially contributing to stem dieback. If you pruned in fall and a drastic cold snap were to cause plant tissue damage during the winter, then the second trimming to remove the dead wood would shorten the stem even more, as opposed to delaying trimming until the worst of winter is past and only making one trim at the height you prefer.
The height to reduce the stems depends on personal preference, and recommendations vary, but one convention is to cut shrub rose stems down to about 15 or 18 inches off the ground, though you could go lower to 12 inches or higher to 24 inches. Roses bloom on new growth (except for many climbing roses that also flower on old growth), so pruning at the end of winter will not remove flower buds. If you delay pruning into April or so, though, you might postpone when those first flowers of the season appear.
If a rose is so rangy that it’s just in the way, like arching over a sidewalk or blocking a hose spigot, you can compromise and make a light trim now to tidy it up so the thorns don’t catch people and then do the main pruning in several months.
By Miri Talabac, Horticulturist, University of Maryland Extension Home & Garden Information Center. Miri writes the Garden Q&A for The Baltimore Sun and Washington Gardener Magazine. Read more by Miri.
Have a plant or insect question? The University of Maryland Extension has answers! Send your questions and photos to Ask Extension. Our horticulturists are available to answer your questions online, year-round.