Keeping your clematis contented

Christopher Lloyd reveals how to prune your clematis successfully, looking at the three distinct groups

-  Christopher Lloyd

ONE of the most confusing aspects about growing clematis is knowing how to look after their pruning and training, so as to keep them in good order and at the same time enjoy the greatest possible wealth of blossom. Attempts have been made to classify them into botanical groups according to the dominant parent in their ancestry. Then we say, “Those lanuginosa or some other group must be pruned in such and such a way at such and such a time.” But this really makes matters only the more confusing as most clematis are of mixed parentage and refuse to conform to one group treatment. And the above ancestral names mean nothing to us since their owners have long since gone out of cultivation.

I think the subject can be boiled down to three basic treatments that tie in with the way a clematis grows and the time it flowers. So here goes, but at the end I shall point out how certain nonconformers give us a choice of methods.

Group 1

In group 1 we have the early, March-May, flowerers. Their flowers are small and they are carried in clusters close to the old shoots or trails made in the previous year. Here belong Clematis montana and the nearly related C. chrysocoma and C. spooneri, their flowers being pink or white. We also have C. alpina and C.macropetala with nodding lantern-like flowers in blue, pink or white; and we have the evergreen C. armandii with scented white flowers.

None of these needs regular pruning; leave them alone for as long as they give you visual satisfaction. But if they grow too large for the space available, or if their legs go bare and woody with greenery concentrated too high up, prune them immediately after flowering - no later than the end of May or early June in most parts of the country. Remove all their flowered trails back to the old wood. Do not let it worry you that you are also cutting away a lot of young shoots. You can safely leave the plant so that there is not a leaf on it.