Pruning roses is necessary for three important reasons: If done correctly, it reduces the likelihood of diseases, it promotes blooms, and it keeps the rose from getting "in the way."
There are a few general instructions that apply to pruning established plants of any remontant rose variety. To begin with, remove all dead, diseased and damaged canes, cutting them back to healthy wood. Also remove any twiggy growth that seems weak compared with the rest of the plant, and any very old, woody canes that have ceased producing flowers. Once all such undesirable growth has been removed, you may go on to shorten the remaining canes.
Regardless of how far back you prune, make sure to use a sharp pruning tool, preferably one with a bypass mechanism. Ragged pruning cuts made with a dull blade invite disease and decay. When at all possible, cut canes back to a point just above an outward-facing bud. Do not make your cut too close to the bud or leave too long a stub beyond it. Cutting too close may lead to injury of the bud and an extended stub will form a roost for pathogenic organisms. 1/4" is an appropriate distance.
First Rule of Pruning Roses: Donít be afraid to prune! Even if you whack away too much, thereís a better-than-even chance the rose will recover.
For repeat-blooming, non-climbing roses, we usually prune in late winter or very early spring. For those who live in warmer climates, this can be done as early as January. For those who live in colder climates, this may not be done until April. For the majority of us, though, we prune our roses between late February and early March. (Note: For those who live in the Southern Hemisphere, change the months appropriately.)
For once-blooming and most climbing roses, we always prune after their first (or only) full bloom flush in the spring or early summer. This can be as late as May or June for many rosarians. If you prune these roses before they bloom, youíve pruned away most of this yearís blossoms. For the most part, climbing roses bloom on "last yearís wood."
General pruning tips:
- Use sharp tools. This reduces the likelihood of injury.
- Wear face, arm and hand protection so you wonít look like something fresh from the butcher shop. :-)
- Donít leave stumps on the bud union when pruning.
These small knobs will decay and could damage your roseís bud union.
[Hint: A fine-toothed saw blade will make clean cuts and permit you to get close to the bud union.]
- Always prune to an outward-facing bud-eye.
Look at the cane and notice the small "pimple" coming from the cane.
Prune the cane at a 45-degree angle such that the cut will be about one third of an inch
(one centimeter) above that bud eye.
- Sealing cuts is not necessary if done during the winter.
On major canes or if sealing is absolutely required, use white glue.
- Never use asphalt-based pruning paint.
[P.S. I define a "major cane" as anything larger around than my thumb.]
- Prune away all "suckers" down to the root from which they come.
A "sucker" is cane growth from the understock of the grafted rose.
On modern hybrid roses, these suckers will always come from below the bud union;
often from the roots. On own-root roses, this does not apply of course.
- If your roses had fungal diseases last year, donít compost your pruned waste.
Most compost bins do not operate at temperatures high enough to kill the fungal spores.
[In this case, itís better to send Ďem to the landfill.]
- Likewise, if you had a disease problem last year,
consider sterilizing the "business end" of your tools after pruning each rose.
This is easily done by dipping the cutting blades into a solution of two
tablespoons (30 ml) liquid chlorine bleach per gallon (four litres) of water.
This procedure will also help if you had a problem with crown or stem gall.
For Hybrid Tea, shrubform roses:
Prune away all dead canes and twiggy growth, and reduce the length of the canes depending on how cold your winters get and how much freeze damage you have experienced. For those who live in colder climates, this may mean reducing the caneís length to 12 to 15 inches (30 to 38 cm). For those who live in more temperate climates, reduce the canes by about one-third of their length. On mature roses, I like to bring the canes back to 28 to 32 inches (62 to 80 cm).
When you are finished, you should have three to five canes extending out from the "bud union" ó that bulbous knob from which all the canes grow. Do not leave "Yís" (branching or forking) in your canes. (Think of an inverted milking stool.) If you have planted your bud unions below soil level or you have own-root roses, the canes should extend from around the center of the shrubís root crown.
For Hybrid Floribunda and Grandiflora shrubform roses: Prune as you would for Hybrid Tea roses. However, branching or forked canes are permitted.
For shrubform, repeat-blooming antique (Victorian) roses, Old Garden Roses, shrub roses, and miniature roses: Prune away all dead canes and twiggy stems, and reduce the size of the rose by about one-third. Prune for shape. [Hint: As a technique, prune off the canes and branches that touch the ground. It allows better access under the rose and reduces pest and disease infestation.]
Pruning rose standards (tree roses): Prune as you would for the type/class of rose above, but only for that portion of the rose at the top of the standard (the "trunk"). That is, if you have a Hybrid Tea standard, prune it as you would for the Hybrid Teas above. After pruning, retie the standard to its support structure if applicable.
Climbing roses bloom on "last yearís wood." That is, they produce bloom stems off of the main canes produced during previous seasons. If you prune these main canes prior to bloom, you will have lost most of this yearís blooms. If, however, these main canes are very old, diseased or "in the way," go ahead and prune them out. They should be removed all the way down to the bud union or root crown, and can be removed while the rose is in dormancy.
On repeat-blooming climbing roses like Hybrid Teas and large flowered climbers, you may prune the "laterals" (the secondary stems coming off the main canes) to a desired length. I prefer to prune back about two-thirds of their length. But other rosarians have more room and only prune about one-third of their length. As a minimum, leave at least two to four leaf buds remaining on each of the laterals. This may be done during the normal pruning time of late winter or very early spring.
On once-blooming or rambling climbing roses, do not prune back the laterals until after flush ó just like the once-blooming shrubform roses. Pruning is accomplished using the same procedures as those for the repeat-blooming, climbing roses.
[Hint: To expedite pruning climbing roses, untie the rose from its support, and carefully bring all the canes into a central work area. After pruning, retie the rose to its supporting structure. Then, further prune the laterals to create the shape you desire.]
Dead-heading is the practice of removing spent blossoms from the rose plant before they have a chance to form fruit. Unless you are particularly interested in growing rose hips, all repeat-blooming roses should be dead-headed thoroughly during the growing season to promote rebloom. Some gardeners prefer to allow the last cycle of blossoms to set fruit, which may encourage plants to enter winter dormancy. As with all other pruning, dead-heading should be performed with a sharp bypass instrument. Remove the spent flower stalk down to a point just above the first outward-facing leaf with five or more leaflets. Make your cuts approximately 1/4" above the leaf axil, leaving the growth bud intact.
Pruning New Rose Plants
Newly planted Old Garden Roses often require a season or two in which to develop their stature as shrubs. This is particularly true of plants propagated on their own roots. I prefer to limit pruning on first-year plants to the removal of dead, diseased, or obviously weak growth. This allows them to put on some added heft during the following season.