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.