Like most flowers, rose bushes benefit from regular deadheading—pinching or cutting off spent blossoms to invigorate continued blooming. It is especially important with hybrid tea roses—shrub roses can be left to their own devices, generally. But more than most flowering shrubs, roses require more aggressive and more regular serious pruning of branches. Again, this is especially important with the hybrid roses. Pruning a rose bush helps to open up the center of the plant to let in more sun and air. It is an important part of a general maintenance or hygiene routine for roses, and it helps prevent common rose diseases, such as powdery mildew and black spot, and to promote good health. Proper pruning also helps the plant bloom to its full potential.
Many gardeners have questions about how to prune roses and the best time of year to do it. The "how" is pretty straightforward and universal. As for the timing, most gardeners prune their roses in spring, but exactly when depends on the local climate and the particular conditions of the season.
Tools for Pruning Roses
There are two essential tools for pruning roses: heavy gloves and sharp pruners. To prevent nasty pricks from thorns, you need thick leather gloves, preferably goatskin, the most puncture-resistant type of leather. For added protection, some gardeners prefer gauntlet-style rose-pruning gloves, which have extended sleeves that cover the wrist and part of your forearm.
Always use good, sharp pruning shears to ensure that you make clean cuts. Rose canes can be tough and will splinter and fray if your pruners aren't sharp. Clean cuts are best for the plant. If you have mature roses, you may also want to have a pair of loppers on hand for cutting heavy canes, especially dead ones.
How to Prune Roses
Pruning a rose bush follows a basic sequence. You start with the leaves, then move on to the deadwood and problematic canes, and finally trim back some of the healthy, vertical canes. In the end, your rose plant probably will look like the victim of an overzealous barber, but don't fret: a good, short cut is what it needs.
Step 1 Remove the Leaves
Pull off all of last year's leaves from the plant, and clean up all dropped leaves from the ground. The dropped leaves, or "leaf litter" can harbor unhealthy fungus.
Step 2 Cut Off the Deadwood
Cut away any dead brown wood, cutting back to live tissue or removing dead canes entirely. If you're not sure where the dead part stops and the live tissue begins, look at the cross-section of the cut: Dead wood is brown on the inside as well as the outside.
Step 3 Remove Problem Canes and Small Canes
Completely prune off horizontal canes and canes that cross other each other. Also remove any canes—vertical or horizontal—that are smaller than the diameter of a pencil at their thickest point. Finally, remove all sucker canes: small canes that sprout randomly off of larger canes and clearly won't amount to much. Very thin canes and suckers sap energy from the plant and are unlikely to produce nice blooms. Better to reserve that energy for the more robust parts of the plant.
Step 4 Trim the Main Canes
At this point, you're left with trimmed, mostly vertical primary canes that may be quite tall, or at least relatively tall. Pruning these back will help promote blooms, and it involves a very specific technique. In addition, some gardeners like to prune their roses quite short, which produces fewer but larger blooms. Others prefer to leave the canes a bit longer, which produces more blooms, but flowers that are smaller.
To prune each cane, inspect the cane closely and identify an outward-facing leaf bud near where you'd like to make a cut. (The buds spiral around the cane from top to bottom.) Cut off the cane 1/2 inch to 1 inch above the outward-facing bud, trimming at a 45-degree angle, with the angle facing in. You cut in this way for two reasons:
- The angled cut sheds rainwater off of the cut end and away from the bud below.
- Cutting 1/2 to 1 inch above the bud ensures that the inevitable dieback below the cut won't reach the bud. Cutting too close to the bud may eventually kill it.
A rose may have several outward-facing buds, so where you choose to cut is up to you. A short cut may leave the canes only 6 to 8 inches from the plant's base. Again, you may opt to leave them longer.
When you're done pruning, the general growth and shape of the plant should tend outward from the base, and then upward, roughly like a hollow vase. This leaves the center of the plant open for sunlight and air.
When to Prune Roses
The best—and safest—time to prune roses varies by climate. Most people prune their roses in the spring, but what "spring" actual means can vary widely. You can always pose this question at a local garden center or, better still, consult the nearest extension service. But there are also a few ways that nature tells you when to prune roses, regardless of your climate or the severity of the current year's weather:
- Follow forsythia blooms. If forsythia grows in your area, watch for it to bloom in spring. Once it does, it's time to prune your roses. Forsythia blooms when the ground reaches about 55 degrees F.
- Check the ground temperature. If forsythia doesn't grow where you live, you can check the ground temperature at a minimum depth of 6 inches. When the ground is warmer than 55 degrees F, you can start pruning your roses.
- Look for leaf buds. Leaf buds appear as small bumps on the canes of roses. As these bumps get larger and redder, they are getting close to opening; this is the time to prune the rose—before the buds open. Typically, this occurs after there are no more hard frosts for the season.