How to Prune Vines

In late winter, when there are likely to be only a few more heavy frosts, it’s time to prune grapes, some clematis, wisteria and roses. Before heading out to the garden, examine pruning shears to be sure they are sharp and in good working order. Dull shears will rip bark and splinter wood which is unsightly, and takes longer to heal than a clean cut, making plants more susceptible to diseases and pests.

Grapes

Pruning grapes is a dramatic event since about 90% of the plant should be removed. The University of Washington Extension Services advises approaching this task fearlessly. Grapes, they say, will recover from the efforts of even a rookie gardener, and since the plant is a vigorous grower, errors can be corrected in subsequent seasons. The Extension Service web site provides excellent, easy to follow directions for pruning new or mature backyard grapes.

Clematis

There are three major groups of clematis vines:

1. Spring blooming,
2. Small flowered, summer and fall blooming
3. Large flowered, summer or fall blooming

The first group produces flowers on last year’s growth, so they should not be pruned until after they bloom in April or May. The second group, according to the Royal Horticulture Society, needs only light pruning to remove dead or damaged wood, and retain the shape of the plant.

However, large flowered, summer and fall blooming clematis produce flowers on new growth. This group of vines needs to be significantly cut back to encourage new growth and abundant flower production. The Royal Horticulture Society advises cutting all the stems to the lowest pair of healthy buds. In most cases, this is only two or three feet from the ground.

Wisteria

This beautiful and vigorous grower needs pruning to maintain its shape, increase flower production and not over-grow its space. There are two schools of thought on pruning wisteria. The first school opts for a heavy, once-a-year pruning in August. The second one also holds with an August pruning, but adds a lighter pruning in February. During the late winter pruning, only damaged wood and scraggly side shoots are removed, taking care not to damage the developing flower buds.

Roses

Where temperatures are mild, February is a good time to prune roses. Gardeners in colder climates should wait until the plants are just beginning to put out new growth, probably some time in March. Pruning methods vary depending upon the type of rose. Many gardening books devote whole chapters to pruning roses, but in a nutshell The Royal Horticulture Society recommends:

• Floribunds (roses with multiple blooms on each stem): trim moderately to shorten or remove weak shoots.
• Hybrid teas: cut back to 3 or 4 strong stems with 4 to 6 buds on each stem. After pruning, the stems will only be 8 to 10 inches high in most cases.
• Climbers: shorten main stems by about a third, and cut side shoots back to 2 or 3 buds to keep the plants from sprawling.
• Ramblers: Do not prune now. This type of rose only flowers in one burst of color once a year. They should not be pruned until after they’ve bloomed.

After pruning vines, the Royal Horticulture Society recommends feeding and mulching the plants so they will have nutrients available when vigorous spring growth begins.