Rose Care: Pruning

Every spring there comes a ritual that many gardeners approach with dread: pruning their roses.

If you are one of this group, the most important thing to remember is that, while your plant may die for any number of reasons (weather conditions, a feeble constitution, poor soil, a lack of water), it won’t die from pruning. Roses are very forgiving on this score – the worst that can happen is that you’ll lose a year’s flowers – and there’s always next year to do the job better.

“Pruning is easy,” says Brad Jalbert of Select Roses. “You could prune with a lawnmower and it would be all right.” He should know. Each spring, he prunes thousands of roses of all kinds, from large climbers to micro-minis, in the display garden at his Langley nursery, and in his three greenhouses.

As spring arrives at different times in different places, Brad recommends pruning when the yellow-flowered forsythia blooms, early March in the Lower Mainland, later in the north and interior of the province. Earlier pruning risks damage from late frosts to the tender, exposed canes, whereas late pruning, even after the rose has already leafed out, will merely delay flowering by a week or two.

Pruning techniques differ with different kinds of roses, but certain tools are essential. Foremost is a pair of good-quality secateurs. Professionals use expensive bypass pruners that will last for many years, but Brad suggests that the cheaper anvil pruners, which are easier on weak wrists, will do a good job as long as they are sharp. Loppers will sever thick canes cleanly, and really old, tough wood requires a thin-bladed pruning saw. As most roses are well-armed with thorns, sturdy gloves are another prerequisite.

Pruning Climbers and Ramblers

These roses are pruned differently from bush roses. It helps to think of their long canes as trunks supporting a series of branches (laterals) that will carry the flowers. For this reason, it is better not to prune a climber for the first two years after planting so that the supporting canes can reach their optimum length. During this time, train the canes at an angle while they are still flexible: the closer they are to horizontal, the more laterals they will begin to produce. If the rose is growing on a pergola or pillar, coax the canes in loose spirals around the supports. Against a solid structure like a garage, fan them as widely as possible.

With an established rose, pruning begins with cutting out any old, unproductive wood at the base and removing dead or damaged tissue down to fresh greenish-white pith. Tip back long canes and secure them to their support at an angle. Brad likes to use black binder twine for this job as it wears well and the colour makes it scarcely noticeable. Next he cuts back hip-bearing laterals to a good bud and removes any old leaves remaining on the stems as they may carry disease spores. For most roses it is better to use pruners for this task as pulling the leaves may tear the bark and leave a wound where disease can enter. After that, it is simply a matter of pruning to shape; the larger the rose, the more wood you can remove to keep it in check.

For climbing roses on a trellis or arch, Brad also advises letting the plants “show off their legs” by cutting off thin, twiggy stems around the base. “They are not going to produce good flowers anyway,” he says. At the end of the season, leave any rosehips to overwinter on the stems; they signal to the plant that it has completed its cycle for the year and can go dormant.

Ramblers, which produce all their flowers at once in early summer, don’t usually need any pruning except to keep their enthusiastic growth in check. When this is necessary, the best time to do it is in summer immediately after the blooms have faded, although this means sacrificing the decorative hips that brighten many of these big beauties in fall. Dead canes can be removed at any time, but Brad likes to leave them as a framework to support the long new growth as well as a refuge for small birds. The new season’s foliage soon covers any unsightly underpinnings.

Pruning Shrub Roses

Unlike climbers, shrub roses should be pruned from the beginning. Usually, the nursery will have done this for you, but if the plant is thin and leggy, you may want to re-prune it after planting.

Hybrid teas and floribundas bloom on new season’s wood and produce most of their flowers on the top third of the bush. They need hard pruning initially to create a strong base for new growth and moderate pruning every spring thereafter to encourage a good show of bloom. “It is far better to prune a rose at least once a year than not to prune it at all,” says Brad. He recommends pruning weak roses hard and strong roses lightly. After a cold winter, all roses may need hard pruning to remove dead wood, but good plants will send up new growth, even if cut almost to ground level. An exception is the well-known ‘Peace’ rose, which reacts badly to hard pruning.

Keep only the strongest canes, removing old, unproductive ones and weak, twiggy growth at the base. If the rose is grafted, inspect your plant carefully for suckers – thin canes emerging from beneath the graft with different prickles and leaves from the rest of the plant. Pull them off at their point of origin or, if that is too difficult, cut them out, but watch for possible regrowth.

Finally, reduce the size of the plant by at least one half, cutting just above buds that face away from the centre of the bush. If any of last year’s leaves remain, clip them off and clean up fallen leaves to prevent re-infection from diseases they may harbour. The result should be a vase-shaped bush with an open centre to encourage good air circulation.

Modern repeat-blooming shrub roses like David Austin’s English roses only require thinning and shaping. Up to 25 per cent of the oldest canes can be removed completely every year to encourage newer, more vigorous growth from the base.

Antique roses that produce a single flush of flowers each year bloom on last year’s wood. Any shaping they require should be done as soon as possible after blooming to allow time for new growth to develop before fall. Exceptions are roses that produce beautiful winter hips; these can be removed in spring when new shoots should be forming behind them.

Fertilizer can be added after spring pruning. Top dress with a good-quality commercial rose food or a balanced organic product, preferably including fish meal. For roses in containers, use controlled-release pellets – 5 mL (1 tsp.) for a 25-cm (10-in.) pot, 15 mL (1 Tbsp.) for a 30-cm (12-in.) pot. “Most roses die from overfertilizing,” Brad warns. “These amounts applied twice in the growing season are enough.”

All fertilizers should be watered in. Water is more important to roses than food, and Brad recommends mulching garden plants with compost or shredded bark to keep the soil moist. Roses in containers need a thorough watering once a day, more often in hot weather.

Of course, even the most attentive pruning and fertilizing cannot rescue a rose that was a poor choice in the first place. With hundreds of roses on the market, somewhere around 2,500 at last count, selecting a good specimen well suited to the Pacific Northwest climate and soil conditions means doing your homework. To protect yourself from being seduced by a pretty picture on a label, do a little research in the library or on the Internet.