Demystifying the Pruning of Roses
"With spring comes crocus and daffodil flowers, the warm sun, the first robin sighting and the task of pruning roses. Pruning roses can sometimes be a confusing task, especially when you might have several different types of roses in the garden such as hybrid teas, old garden roses, shrub roses, and climbers," said Greg Stack, a University of Illinois Extension horticulturist. "With this confusion comes doubt and doubt sometimes leads to improper pruning or no pruning at all. The type of rose you have and the time of year it blooms will influence the type and amount of pruning. General pruning practices can apply to all types of roses, but there are differences between classes."
The amount of pruning between species roses and hybrid teas is vast with the species types needing less severe annual pruning and the hybrid teas needing the most severe pruning for optimum flowering.
"A common thread in pruning involves some principles that apply to all classes of roses: remove dead, damaged and diseased canes; increase the air circulation within the plant; keep the shrub from becoming a tangled mess; shape the plant; and encourage the growth of flowering stems," he said.
"The majority of pruning is best left for the spring. Wait until the weather has stabilized a bit when temperatures are not going to fluctuate too dramatically. A good guide might be when the forsythias start to bloom."
The basic pruning fundamentals that can apply to all classes of roses across the board include: use clean shape tools; cut at a 45 degree angle above an outward facing bud; remove all dead winter injured canes that can be identified as shriveled, dark brown or black; after making cuts seal the ends of the canes with something such as white glue, or pruning paint as this helps to prevent entry of cane borers; remove thin weak canes smaller than pencil size in diameter.
"With this basic pruning tasks accomplished you can center on some specific pruning practices that apply to specific classes of roses," said Stack.
Roses such as hybrid teas, grandifloras, floribundas and miniatures producing the best flowers on new or current season canes will require the most severe annual pruning. This usually means removing about one-half to two-thirds of the plant's height and reducing the number of canes.
Again, remove all dead canes due to winter injury. After that remove the thin weak canes leaving about three to five stout canes. These canes are then cut back to about four to six inches leaving about three to five outward facing buds.
"Modern shrub roses are very popular types of roses and many gardeners are including them in their plantings," he said. "This class of rose bears flowers on mature canes that are not old and woody. If severe pruning were done to these roses it would result in reduced flower production.
"Generally these roses don't need much pruning the first two to three seasons in the garden other than perhaps reducing the height a bit. In this case, cut the canes back by about one-half."
When more extensive pruning is needed in order to maintain quality blooming canes a method called the "one-third" method is used. In the spring, remove about one-third of the very oldest canes by pruning them right to the ground. This helps keep the plant from becoming and overgrown tangled mess of poor flowering canes and opens up the plant for new replacement canes. The remaining canes are then cut back by one-half.
Old garden roses are often great additions to the garden, because they combine a very classic rose flower shape with fragrance that is very hard to match with any other class of rose. These roses are often pruned much the way you would prune modern shrub roses.
"However if you have once blooming old garden roses such as Gallica, Centifolia, Alba, Moss Rose or Damask you need to remember that these roses bloom on old canes produced the season before," he said. "So the majority of pruning is done right after flowering and not in the spring. Heavy spring pruning would remove the flowering canes and result in little or no flowers that season.
"Thinning and removing the very old canes is encouraged in order to open the plant up and stimulate new cane growth. Repeat flowering old garden roses such as Bourbons, Hybrid Perpetuals, and Portlands bloom on both old and new canes. These can be pruned before they flower without having to worry about losing any type of the blooms in the spring."
Climbers and ramblers may need several seasons in the garden before a lot of pruning is needed. In most cases, pruning is limited to removing winter damaged canes. Pruning is similar for both of these types of roses.
"The difference is in the timing," Stack explained. "For ramblers that are once blooming, pruning is done right after flowering. Climbers tend to be repeat bloomers so they are pruned in early spring. Reducing the side shoots or lateral canes to about 3-6 inches helps to stimulate flowering. Also, training the canes to a more horizontal position encourages the growth of side shoots that are bloom producing shoots."
The one frustrating consequence of including climbers in the landscape is that many are not very good at going through the winter without a lot of cane damage, he added. This damage then needs to be cut back and you often lose a lot of the plant that you worked so hard to grow and cover a trellis or arbor. To minimize or almost eliminate this problem, you might consider growing some hardy climbing roses that will result in little cane damage.
Stack noted that there are a number of excellent 'Kordesii' and 'Canadian Explorer' types that are grown as climbers and overwinter nicely even without any type of protection. Look for 'Blaze Improved', 'Henry Kelsey', 'John Cabot', 'John Davis', 'New Dawn' and 'William Baffin'. All will do a nice job of covering arbors and trellises and show very little winter injury.
"So, pruning roses is not a big mysterious garden chore that is left to only seasoned rosarians," he said. "With a little understanding of some basic principles and an understanding of the slight differences between some classes, your rose garden should be the best ever."