To keep plants in great shape you need to prune them. Different varieties need tackling at different times of the year, so to make your life easier, clematis are divided into several pruning groups based on when they flower. Here’s how to tackle the plants in your garden.
Winter, spring and early summer flowering clematis
Known as Group 1 by experts, this includes C.alpina, C.macropetala and Clematis montana, as well as evergreen varieties such as C.armandii and winter flowering C.cirrhosa. These need minimal pruning to remain floriferous. Simply remove dead or dying growth, and keep plants within bounds by pruning just above a leaf joint after flowering.
Double flowered varieties and those that flower twice in summer
Known as Group 2, this includes clematis that produce two flushes of flowers – in early summer on wood produced the previous year and a second on new shoots in late summer. It also includes most clematis that have blousy double and semi-double flowers, such as 'Elsa Spath', 'Fireworks', 'Horn of Plenty', 'Lasurstern', 'Mrs Cholmondeley', 'Niobe', 'Royalty' and 'Vyvyan Pennell'.
Prune plants in winter or early spring, removing dead or weak shoots, and keeping long stems within bounds by trimming back to a pair of buds. Cutting back encourages new growth from lower down the plant and brings the flowering height down. Don’t be too enthusiastic with your pruning or you may remove the first flush of flowers.
Late summer and early autumn flowering clematis
Clematis tangutica and its clan, along with large flowered climbers, such as 'Comtesse de Bouchard' and 'Hagley Hybrid' belong to group 3. These should be pruned annually in late winter or early spring. To do this, cut plants back hard. A foolproof way of doing this is to work your way up from the base of the plant and cut stems above the first pair of healthy buds you find. Don’t worry, plants will soon produce new shoots.
What to do next
Ensure plants bounce back vigorously after pruning by working a general purpose granular fertiliser into the soil with a rake. Water, then cover the area above the plant with a thick (3-inch) mulch of leaf mould or well-rotted manure, making sure it does not come into contact with the stems.