Clematis is a genus of climbing vines popular in gardens for their very showy flowers and attractive, whirlwind-like seed clusters shortly after. Since the flowers are the most important aspect of these plants, their bloom time dictates when and how to prune.
This article outlines general pruning care and things to think about for clematis pruning. Once you know a little about your own plant, my step by step guide will take you through pruning your specific variety.
Clematis is the scientific name and the most common name for this group of plants, but some of the old and popular species are also called traveller’s joy, virgin’s bower, and old man’s beard.
The First Winter: Cut Back to Develop the Roots
If you just planted your clematis, you might consider sacrificing green growth and flowers in exchange for root growth that makes a strong plant in the long-term. Ruth Gooch, author of Clematis the Complete Guide suggests hard pruning all one- to three-year old clematis down to the second set of strong buds above ground level.
This method will sacrifice most of the flowers if the plant is a spring-bloomer. This is worth it if you can wait for flowers, but maybe you can compromise with your plant: you might try cutting down nearly all of your vine as Ruth suggests, but leaving a few trained canes up until they flower.
Training Clematis Vines
Clematis are fast growers that cannot support themselves. If you don’t want them scrambling across the ground and nearby shrubs, you must provide an armature such as a trellis or arbor. Make sure your armature is strongly built, perhaps anchored to a wall. Expect to have to tie your clematis to it, or at least periodically wrap the plant to the structure by hand. Don’t expect a wall alone to provide support: unlike ivy, clematis cannot cling to a bare vertical surface.
By the way, you certainly can try letting your vines scramble on the ground or perhaps on a nearby standing dead shrub, for a more informal look. Your work to control the display may be harder, and you may need a lot more space than if you just dedicated a trellis to the cause. But it’s your garden—your rules.
When to Prune Clematis
Flowers are the most important impact of clematis, so keeping them blooming strong, every year, is our main goal for pruning clematis. Step one: know when your clematis blooms:
- Early-spring blooming: prune right after flowering has finished.
- Mid-spring or later blooming: prune in early spring before buds swell and growth begins. How you cut, however, will depend on whether the plant blooms in spring or late summer, as detailed below.
How to Prune Clematis
In pruning clematis, your overall goal is to create a plant that will flower strongly each year at various heights from ground level to a comfortable height where you can enjoy and reach the plant for maintenance. By pruning you control size, keep the plant trained to its armature, and create the space for new growth to replace old wood.
Take a step-by-step approach to pruning clematis. Start by deciding what size you wanted your plant to eventually be at maturity. This is probably determined by the size of your armature, but keep in mind that you want to be able to reach the top to prune and train it. Are you willing to climb a ladder?
Continue your pruning by noting your variety of clematis, when it will bloom and if it will develop wood. At the right time of year, cut back late bloomers to the ground and matured spring bloomers to their original framework of tidy, strong, trained stems.
Finally, if it’s a woody clematis, select old canes to cut back all the way to the ground, stimulating strong new growth, a textured look, and exposing all levels of the plant to light and new growth.
Will you deadhead? Deadheading sends energy to create more flowers, but prevents the whirlwind-like seedheads from forming. I really like the seeds and would let them form, but you can do a little of both if you have the time.
Common Mistakes in Pruning Clematis
Too afraid to prune. If you’re just too busy, I forgive you, but if you never prune your clematis because you are afraid you’ll do wrong . . . well, don’t be. If you ignore any vine it will fast become a weed, and clematis are too special to be weeds. Neglected clematis grow tall and bear flowers too high to see, or scramble all around, shade themselves, and bear flowers sparsely. You can do better.
Pruning hard at the wrong time. If you prune a little, it’s okay to prune at the wrong time. If you prune at the right time, it’s okay to prune a lot (“hard”). But if you prune hard at the wrong time, especially if you are shearing off the whole outside of the plant (a bad technique) you won’t see any blooms this year.
If you can’t figure out when to prune because you don’t know when the plant flowers, prune hard just what you need to to keep the size reasonable, and let the rest go for a year.
Gooch, Ruth. Clematis The Complete Guide. The Crowood Press, 2001 .