Here, we continue to fine-tune our aim on the topic of pruning that much-loved vine, the clematis.
I've read what you've written about clematis pruning and am still unsure. I've never pruned my clematis vine. I love it, and I'm afraid to lose it! Can you clarify -- is it really necessary to prune it? What if I don't know what kind it is? -M.A. -
Please just cut it, even a little. No matter what kind of clematis it is, it will grow back (more in Clematis Grows Back), better looking and healthier.
Lots of authorities say this, beginning with masterful English gardener and author Christopher Lloyd, who tended his world class garden at Great Dixter and grew clematis at his nursery, Greater Dixter:
An unpruned clematis looks like a disemboweled mattress -- a painful sight. From year to year its owner grows more despairing; his only comfort is that the birds are nesting in the tangle and perhaps not all of them are sparrows.
- Christopher Lloyd, in his book Clematis -
Regular pruning of clematis encourages strong growth and flowering and keeps the growth in check. If left unpruned, clematis can turn into a mass of tangled stems with bare base and flowers well above eye level.
From the Royal Horticultural Society clematis resource
All too often I have seen a perfectly good little clematis which has been planted out and allowed to develop one very long, spindly growth. And the owners have complained that either it's a weak plant or it doesn't flower well when the only real problem is how it's been treated.
- Susan Austen, owner, Completely Clematis Nursery -
So prune your clematis to help it stay young, healthy, vigorous, and most productive in bloom.
As for what kind of clematis you have (more in Clematis Types) and what difference that may make in pruning, you can follow the directions in Growing Concerns 511. (We've recently tweaked that article; thanks for letting us know we weren't quite clear enough.)
Or you can simply proceed by the works-for-everything method. That is, treat every one as if it's a Group 2/Type B clematis:
At the base of the vine, select one or more old canes* and cut those to the ground. Then trace those cut stems up, clipping (not yanking) to detach and disconnect the severed bits from the rest of the plant. Finally, cut all the remaining stems back to a spot where there are strong, plump buds or new growth.
*Pruning a vine that has only one cane? Cut that one back so the plant can develop multiple stems and thus have a fighting chance against clematis wilt disease. If possible, cut that one cane to about 6 inches tall, then dig a short trench, lay it down in that trench and cover it so only its tip is above ground. The buried nodes (the places where growth such as leaves or roots can develop) will react to moist darkness by producing new roots and the nodes near or above the surface will produce new shoots.
What are the consequences of pruning Group 1 or 3 clematis like group 2?
The Group 1, spring blooming clematis will have fewer blooms that year because you will cut off a good portion of what matured and became ready to bloom during the previous summer. However, if you continue to prune regularly per Group 2 directions even a Group 1 clematis will have developed so much new wood from its base the previous year -- wood that does not get cut off -- that what remains after the annual pruning will be full of flower buds.
Group 3, late blooming clematis treated like Group 2 may lose value as a double-up weaver. Late blooming clematis are often planted to grow up through an earlier blooming host, such as a once-blooming climber rose or a weigela. In those partnerships the host must have time in the sun in spring and early summer to be healthy and perform well. If the space sharing clematis is not cut all the way to the ground in spring -- cut back only partway a la Group 2 -- it may be too tall and leafy too early, casting so much shade on its host that it diminishes the duo's First Act.
Now you've gotten us thinking about additional exceptions, such as when we want to treat Group 3 clematis like it's in Group 2 to avoid having to retrain it each year. Yikes, that means more tweaking, and this before we've even published this reprise! So try this: This year, just cut your clematis. Watch it grow back. Then when you're confident of that, come back and check out our footnote, Low or lower .