How to Prune Roses
Pruning is about more than just looks. Proper pruning improves the health of your rose bush, prevents disease, and encourages better flowering.
There are different pruning strategies for different times of the year, but overall the goal is always the same: to keep the bush vigorous and open, allowing better air circulation through the center of the plant.
Air movement dries the leaves, which helps prevent foliar diseases. Fungal diseases like black spot and powdery mildew are more common on plants with congested growth in the middle of the plant.
General Pruning Guidelines
Whether you are deadheading blooms during the summer or performing your annual spring cutback, it is important to consider how a rose grows. How you prune a particular rose will always be the same.
- Pruning cuts should always be made just above a bud eye. "Bud eye" refers to the area on the stem where branching occurs. In the summer, it's easy to figure out where to prune, just cut right above a set of mature leaves.
- On roses, there is always a dormant bud where leaves attach to the stem. You'll have to look a little harder to find the bud eye on dormant or older canes; they are located just above the crescent-shaped leaf scars along the stem.
Roses Respond Well to Pruning
What is interesting about roses is their willingness to break bud on old wood. Not all shrubs have this ability. Junipers, for example, rarely leaf out on old stems; cut back too far, and you are looking into the dead center of the shrub. Roses, on the other hand, are capable of sending new shoots out of old branches, even if they are size of a tree trunk! This is good news for the novice pruner, for it is nearly impossible to kill a rose by over-pruning. It also means you can rejuvenate older bushes by cutting them nearly all the way to the ground.
Make the Cut
Make a slanted cut just above an outward-facing bud eye. Cutting at a slant helps water run off of the wound, which prevents water from collecting on the end of canes, as well as being more aesthetically appealing. After making this cut, the rose will direct its growth to the closest bud, sending out a new terminal shoot. Choose an outward-facing bud eye to ensure that the new growth is directed away from the center of the plant. It is generally not necessary to put anything on the pruning wound. You may apply Elmer's Glue-All over the cut if rose cane borers are a problem-pest in your area.
Pruning for Health
Basic rose pruning involves the 3 Ds: removing dead, damaged, or diseased branches. Dieback is common in roses and most often occurs when a pruning cut has been made in the middle of a branch as opposed to at the bud eye. Since the rose wants to direct growth into the terminal bud, any portion of the branch left between the pruning cut and next bud eye will die back. Sometimes the closest bud eye is not viable, in which case dieback would occur farther down the stem to the next healthy bud. Dead wood is typically brown in color but may also be blackish if caused by winter cold damage or frost injury.
As part of its natural defense system, the rose will attempt to quarantine dieback and create a clear break point between healthy tissue and dead tissue. However, depending on the cause of damage, there may be a leading edge of dying tissue advancing down the stem. For this reason, it is always a good idea to prune dead wood out, no matter what time of year it is. Look at the color of the stem to see if you've cut back far enough; dead tissue often extends farther down the center of the stem. Healthy branches will be pure white or light green in cross-section. Any discoloration indicates dying tissue and should be cut out.
Damaged or diseased wood is also easy to spot, and often goes hand in hand as damaged areas create entry opportunities for diseases. In roses, damaged areas are common on crossing branches, where motion from wind causes thorns to rub against adjacent canes. Wind damage can also occur during the main growing season when top-heavy branches laden with blooms snap in half during stormy weather. Diseased branches usually involve some type of stem canker or lesions from fungal diseases like black spot or downy mildew, and should be removed promptly to prevent the pathogen from spreading.
Seasonal Rose Pruning
There are differing opinions about when to prune roses. Some people like to prune in the fall, some in the spring. Heirloom says: both (with the exception of once-blooming roses, which should be pruned once just after flowering, see section on "Special Situations"). In addition, grooming your plants during the summer will present a more appealing form. Let's take a closer look at the pruning goals for each season...
Prune to prevent wind breakage, whipping, and scarring by long canes. Observe your roses on a windy day to gauge potential problem areas. As a general rule, you should prune out all canes thinner than a pencil in diameter on hybrid teas, shrub roses, and climbers. These thin canes tend to whip around in the wind and will scar their neighbors. You should also remove any errant crossing branches for the same reason.
Pruning long canes will prevent the possibility of the roots being loosened as a result of strong winds or freeze/thaw cycles. Wind also pulls moisture out of plants, so reducing the overall volume is helpful. Shorten all canes to chest height as a winter protection measure. Prune all large climbers back to where they can be securely tied to their support structure.
Prune late enough in the growing season so that pruning will not stimulate new tender growth that would be damaged by an early freeze. In the Pacific Northwest, late October or early November is usually the optimal time. Be careful not to over-prune in the fall. A general guideline is to reduce the overall height of the plant by 1/3 and thin the center out slightly to accommodate stronger wind gusts.
Rejuvenate roses with a hard annual pruning. Prune to shape and clean out dead wood, and worn out, weak, spent canes. Spring is the time to correct problems with overall form, or reduce the height of roses that are outgrowing their space. Most roses bloom on new wood, and tend to have reduced bloom on old canes. Let the "Rule of Thumb" be your guide: New growth about the diameter of your thumb make the best canes. If the branch is bigger than your ordinary loppers can tackle (1-1/2 inches or larger), it should be removed.
For most rose bushes, leaving 6 to 8 strong, healthy canes is ideal to produce a full, shapely plant, without overcrowding. Floribundas or shrub roses tend to have more branches by nature, so you may want to leave more canes on those types of roses. For most roses, spring pruning should reduce the overall height of the bush to 18 to 24 inches. The shorter you prune, the fewer blooms you will have, but the blooms will be larger. Leaving taller canes will produce smaller blooms in more abundance. Remove all dead, damaged, and diseased canes, crossing branches, and thin so the bush is open and ready to accommodate new growth.
Spring pruning is really dependent on the weather. Most people in the Pacific Northwest prune their roses in either late February or early March. California growers typically "spring prune" in January. Midwest patrons may have to wait until early May. Keep an eye on your plants and the temperatures; time your pruning just as the new growth starts. You generally don't want to prune if there is still a chance of a hard frost, which would damage the tender new growth. If new growth is damaged by temperatures below 25 degrees, you may have to re-prune shorter, but this shouldn't happen very often.
Deadheading (removing spent blooms) will prevent seed hip formation, encourage new blooms, and keep the shrub attractive. Remove the spent bloom by making your pruning cut down the cane, just above an outward-facing set of mature leaflets. Mature leaflets are usually 5 to 7 in number; immature leaflets only have 3 leaves. If you prune back to only 3 leaves, you will not get any new growth or re-bloom.
Floribunda or hybrid musk roses that bloom in clusters present some unique challenges. The individual flowers should be deadheaded as they fade, then the entire truss pruned back to a mature leaflet once all the flowers have bloomed. Keep in mind that deadheading removes hips that would form later. You may not want to prune once-bloomers until after their hip display for this reason. Some repeat bloomers, such as Rugosa roses, produce hips and blooms at the same time. This attractive display may appeal to you and you may not want to deadhead them. Repeat bloomers can be deadheaded until August, and then allowed to develop hips after their last flower display.
Other summer grooming includes pruning for maintenance (to keep a larger bush within bounds, or to keep roses from encroaching into a walkway), pruning to shape, and pruning to remove poor branching connections. You may also want to remove aborted buds that have failed to open due to rain. Always remember to make clean pruning cuts with a sharpened blade and to periodically disinfect pruners between cuts if you are removing diseased branches.
Remember that large-blooming rose varieties need a sturdier cane to support the weight of the flower. If you don't prune back far enough on the stem, the new growth will be too weak to support the bloom and you will end up with a bent cane whose flower looks at the ground. Instead of pruning back to the first mature leaflet, you can cut farther down the stem to force stout new growth. Don't prune out the entire cane. It is good practice to leave at least two mature leaflets on the stem when deadheading.
Once-blooming Roses: Old garden roses that bloom only once a year produce flowers on old wood. This is growth that appears the year previous to any blooms it produces. Once-bloomers should only be pruned immediately after they finish flowering (generally around mid-July). If you prune in the spring, you will lose all of that year’s bloom. Old garden roses can be pruned to 15 inches every other year without damage. This keeps a large bush within bounds and provides shaping. If you don’t mind the size of the bush, then only prune for dead, damaged, and diseased canes or other growth that is undesirable to you.
Hedge Roses: If you desire a hedge, roses should be planted closer together than normally and should be treated as a unit. Prune for an even growth production.
Roses in Pots: Pruned the same way as those in the ground. Generally pots are on the patio or near a pathway. Keeping the bush trimmed so it doesn’t snag the passerby.
Roses that Colonize: This group produces new growth from the roots and spread out to cover a large area. Some Gallicas and a few Centifolias do this. Instead of pruning at the soil level, just use a shovel and dig up the extra growth. Give to your friends or plant in new locations of your own garden. This is how many roses were transported from one part of the country to another in the early days of wagon trains. ‘Harison’s Yellow’ is one such example.
Groundcover Roses: Grow wider than they do tall. If your groundcover rose is outgrowing its space, resist the temptation to chop the ends of the lower branches. These roses should not be pruned in a vase shape, as that will direct their growth upward instead of outward. In general, shearing roses like topiary shrubs is a bad idea, and it will be difficult to recover the form of the rose. If a branch is getting too long, follow that cane all the way back and remove it at the center.
Hybrid Musk Roses: Prune lightly to remove spent bloom clusters and maintain a rounded bush that is 3- to 4-feet tall, or more if you have room. Hybrid Musks tolerate severe pruning if space is limited.
Miniature Roses: Should be cut back by 1/3 in the spring. These roses are very resilient and may be pruned at any time of year.