Pruning and Training Climbing Plants
Climbers stand on other plants’ shoulders to reach the light, then hog as much of it as they can. As a result, they may grow up out of sight, leaving their trailing bare stems behind—not ideal in a small garden. An easy remedy is to cut them back severely, either in late winter, as for many late-summer- or fall-flowering clematis, or every few years, as for honeysuckle. Climbers that flower early in the year and bloom on stems made the previous year should be trimmed after flowering.
When to Prune Climbers
Different types of climbers require pruning at different times of year—often depending on when they flower and whether the flowers appear on new or old stems. Clematis fall into three main groups: those that flower in late winter or spring; those that flower in early summer; and the later-flowering types that bloom from midsummer to fall. For the best flowers, each should be pruned in a different way. Some woody climbers, including actinidia, parthenocissus, and wisteria, should be pruned in winter when dormant, like many trees and shrubs, although wisteria needs further pruning in summer for the best results.
Pruning and Training Wall Shrubs
Certain shrubs, while not actual climbers, can be treated almost as if they were by growing them against fences, walls, and trellises. Use the same pruning methods as for freestanding plants, but tie in stems during the summer in order to guide growth over the surface to be covered. At the same time, shorten any shoots that are growing away from the wall to make sure the shrub stays neat and narrow.
Pyracantha, cotoneaster, and ceanothus make excellent wall shrubs; all flower in spring at the base of stems made the previous year. Make sure that the wall is in good condition before fixing a trellis to it, as any repairs will be difficult once the plant is established. When pruning, take care not to cut back too hard into the old wood if you want blooms and berries. Shorten all new sideshoots in midsummer, leaving two to three leaves to encourage flower formation the following year, and to make any berries more visible. Pyracantha can be trained up a wall or a fence like a climber. New berries are formed at the base of stems made the previous year, so take care not to prune them off.
- Early-flowering clematis (including Clematis montana, C. armandii, C. cirrhosa, and C. macropetala) need little pruning. After flowering, give them a light trim, cutting back too-long or unproductive stems to a healthy bud. Renovation is possible for old, straggly plants: cut back all stems almost to the ground, but do not repeat this for at least three years.
- Early- to midsummer flowering clematis can be left to their own devices, unless the plant needs restricting, when a trim after flowering will help. For renovation of old, tangled plants, cut back to buds near soil level in late winter. You may either lose that year’s flowers, or the plant may flower later in the summer as a result.
- Late-flowering clematis, which do not flower until late summer or fall, are pruned in late winter or early spring when the buds are starting to swell. Prune them down to a pair of plump, healthy buds about 12 in (30 cm) from the base. Alternatively, if you are dealing with a vigorous type, it can be cut down to the ground.
Pruning an Established Wisteria
Wisteria is a special case, where shortening the sideshoots promotes the formation of flower buds. You will need to prune twice: once in summer, and again when the plant is dormant in winter. For large plants, you may need a sturdy ladder to reach the top.
- In summer, after flowering, prune back the sideshoots to within five to seven leaves from the main stem, and tie in new growth.
- In winter, shorten the new stems that have formed after you pruned in summer. Take these back to leave two buds. The short sideshoots that are left will produce lots of spring blooms.