I have always been a strong believer in the value of a well-placed flowering vine. Fast growing annual vines such as moonflowers, morning glories and cypress vine are excellent quick fixes for many garden conundrums, and I never seem to have any trouble finding a spot for yet another climbing rose. But it is the beauty of a perfectly positioned clematis that most often catches my attention. It is no wonder that this plant is referred to as the "Queen of the Vines." However, if you have ever tried to wrangle with the challenge of how and when to prune a clematis, a much different name might come to mind.
As a general rule of thumb clematis can be broken down into three major groups and you prune your clematis according to which of these groups your plant belongs. If you feel the least bit timid about cutting away at your plant, take heart. The important thing to remember is that even if you make a mistake you are not likely to kill the plant.
Early Flowering Clematis
These clematis bloom on 'old wood' meaning flower buds form on the previous season's growth. They also flower earliest in the season, usually sometime between April and June depending on which zone you live in. Prune this group of plants immediately after flowering. This will allow enough time for new growth to produce flower buds before winter. These clematis only need light pruning and removal of dead stems. If you feel your vine has grown out of control it is okay to cut it back hard, but avoid cutting into the old woody trunks.
Large Flowering Hybrid Clematis
The clematis in this group produce a heavy display of large flowers in June on old wood and will often bloom again in late summer on new growth. This makes them somewhat of a challenge to prune.
The best time to prune these plants is in February or March. Begin by removing any dead stems or weak growth. Working on one stem at a time, cut back the top 6 to 18 inches. Make the cut just above the uppermost pair of large, healthy buds.
The largest flowers are produced on old wood so you don't want to cut these clematis back too hard before the first bloom cycle. A better time to regain control of overgrown vines is immediately after this first flush of bloom.
Late Flowering Clematis
Logistically this is the easiest type of clematis to prune, but emotionally it is a bit tougher because it is difficult to sacrifice healthy stems and buds. Just keep in mind that these clematis bloom on the current season's growth and given time, you will be rewarded for this brutal act with vigorous new stems and an abundance of beautiful blooms.
In February or March take each stem and cut it back to a height of about 12 to 24 inches leaving at least two sets of large buds.
A Few of My Favorite Clematis
- 'General Sikorsky' - yellow centered flowers with medium blue petals; 6' - 8', hardy to zone 4; blooms June - August; pruning group A
- 'Will Goodwin' - stunning ruffled blue flowers; 8' - 12'; blooms June - September; hardy to zone 4; pruning group B
- 'Mrs. Cholmondeley' - huge 7" - 9" lavender flowers with brown centers; trouble free; blooms May - June then again in September; 12' - 16'; pruning group A or B
- Clematis montana Odorata - masses of small light pink, sweet smelling blooms on a vigorous growing vine; hardy to zone 6, will grow in zone 5 but there is a risk of winter kill; 20' - 30'; blooms May - June; pruning group A
- 'The Duchess of Albany' - abundant pink, bell shaped blooms; showy golden seed heads; 8' - 12'; blooms July - October; pruning group C
- C. viticella 'Etoile Violette' - deep, velvet purple blooms; 8' -12'; blooms July - September; pruning group C
- 'Comtesse de Bouchard' - mauve-pink flowers; very tough and floriferous; blooms June - September; 8' - 10'; pruning group C
- 'Henryi' - large, flat white flowers; 12' -15'; blooms June - September; protect from strong winds; pruning group B
- 'Belle of Woking' - double sliver-mauve blooms; blooms May - June and then again in September; 6' - 8'; pruning group B
- Sweet Autumn Clematis - small, highly fragrant, white, star-shaped blooms; blooms August - September; 20' - 25', pruning group C