When spring arrives, many gardeners feel a moment of anxiety and incomprehension when faced with the tangled mess of branches that is their clematis. What should they do with all this? Cut back to the ground? Don’t prune? Pruning group 1, 2, or 3? Help!
Today is the day we’re going to demystify clematis pruning with ease. Because, in truth, pruning clematis simply makes sense when you better understand the different growth habits of these plants.
The Best Time to Prune… or Not
First of all, it is important to note that clematis pruning is only done on plants that have reached full maturity. Therefore, for the first 3 to 5 years of a clematis’ life in the garden, it’s simply left to grow without any intervention.
Then, if you need to prune a clematis, this pruning is ideally done in early spring, before the leaves appear. That is, for northen gardeners. As soon as the snow has melted and the water has been well absorbed into the soil, you can start pruning. Even better, wait until the buds are just beginning to swell. As long as the leaves haven’t appeared, pruning is possible. Personally, I prefer to wait until this period of bud swelling, because it’s easier to distinguish the living stems from the dead ones.
What Are Those Groups We See Everywhere?
To make pruning easier to understand, experts have divided clematis into three main categories. Each group includes hundreds of clematis cultivars. Pruning is the same for cultivars of each group. For example, all clematis in group 1 are pruned the same way.
So, to know how to prune your clematis, you first need to know the variety. Plant identification software and apps can help you with this task. Some websites also offer lists of varieties specifying the pruning group.
Pruning Group 1 – No Pruning!
These are spring-flowering clematis, such as ‘Blue Bird’, ‘Rosy O’Grady’ or ‘Ruby’. They are actually descended from the species C. macropetala and C. alpina.
Everything makes sense here! These clematis bloom early in spring, which means the flower buds are already well formed. Pruning necessarily removes flower buds. Therefore, don’t prune them before the leaves appear.
Over the years, of course, a little tidying up becomes necessary, as the tangle of dead branches can become unsightly. Also, under good growing conditions, the plant may have grown where it isn’t wanted. In these cases, wait until just after flowering to gently detach the plant from its growing structure. Then carry out the necessary cleaning and pruning. This gives the plant ample time to form new shoots and, hurrah!, new flower buds, which will be ready for the following spring.
Pruning Group 2 – The Happy Compromise
Pruning group 2 clematis are the happy compromise group. These are plants that bloom on both the previous year’s wood and this year’s new shoots. Thus, you could say that they have a prolonged flowering period. Also, they are large-flowered clematis. In countries a little further south, these clematis are called early-flowering clematis, but here in northern North America, there is barely a week or two between the early-flowering clematis of group 2 and the late-flowering clematis of group 3! The earliness of flowering is therefore more difficult to discern.
In short, because of their two modes of flower bud production, pruning is practiced to preserve some of the old stems, but also encourage the development of new shoots. Generally, those clematis are pruned to about one meter (3 feet) from the ground. In this way, the preserved stem buds will emit the shoots that will produce the first wave of flowering. Then, later in the summer, the new stems will produce a second wave of flowers.
In this group we find clematis like ‘Nelly Moser’, ‘The President’, ‘Asao’, ‘Moonlight’, ‘Mrs Cholmondeley’ and most of the pompom-flowered clematis!
Pruning group 3 – Cut it Down to the Ground!!
Well, not exactly way down to the ground. Pruning group 3 is another easy-to-prune group: it’s the one where you cut everything back! Indeed, those clematis develop flowers on the new shoots. These are therefore plants that can be cut back to 15 cm (6 inches) from the ground each spring.
The very famous ‘Jackmanii’ clematis and its variants (‘Jackmanii Superba’) are part of this group. This is also the case for ‘Hagley’ Hybrid’ (also called ‘Pink Chiffon’), ‘Comtesse de Bouchaud’ and all clematis hybrids of C. viticella, such as ‘Madame Julia Correvon’, ‘Étoile Violette’ or ‘Betty Corning’.
In conclusion, if you’re in doubt, follow Larry’s advice: just don’t prune! Yes, it’s a fact. Even without any pruning, all clematis, regardless of their group, will continue to grow and worse… to flower! Isn’t that beautiful!
