How to Prune Three Different Clematis Groups Properly
Clematis need pruning to maintain their gorgeous blooms. However, proper pruning depends on when the clematis flowers and whether it blooms on old or new growth. This article will provide you with tips to prune your clematis properly to encourage prolific flowering and strong growth.
While clematis plants are known for their masses of vines adorned with stunning flowers, they need to be regularly pruned to prevent becoming a mass of tangled stems. Regularly pruning a plant manages its size and shape and also helps encourage strong vine growth and prolific flowering.
However, you need to prune them correctly. If pruned improperly, you could end up with a plant that stops flowering completely.
Clematis plants are classified into three different groups, which are defined by when they flower and if they bloom on new growth or old vines. These characteristics determine when and how to prune your plant.
Sometimes called “Group A” or “Type A,” these clematis varieties tend to be larger plants that bloom very early in the season. These blooms burst on old growth from the previous year. Group 1 includes the C. alpina, C. armandii, C. cirrhosa, C. macropetala, and C. montana.
Also known as “Group B” or “Type B,” Group 2 clematis bloom later than Group 1 and earlier than Group 3. The first flush of flowers opens in late spring, with a second bloom erupting in late summer. Buds develop on a combination of old and new growth. Species in this group include C. florida and C. patens.
Group 3 clematis are the latest blooming varieties, flowering in late summer or early fall. They bloom on the current season’s growth. Group 3 includes C. viticellas, C. orientalis, C. tangutica, and C. texensis.
Since Group 1 clematis flower on old vines, the general rule of thumb is to trim lightly. Severely pruning these plants removes all developed buds, resulting in a plant that won’t flower.
Instead, you can trim or shape them lightly just after they finish flowering for the season. Trim back no more than one-third of the plant as they do not like severe pruning. Pruning them after flowering encourages new growth that develops buds for the following year.
Group 2 clematis are a cross of the other two groups. Some flower buds develop on wood from the previous year and some form on the current season’s new vine growth. A light pruning is best with this type unless the plant has grown too large for its allotted space.
Plan to prune Group 2 clematis in late winter or early spring just as active growth starts for the season. Wait until the flower buds turn green and begin swelling, as this makes them easier to see.
Start at the top of each vine and work your way down. When you reach the first pair of strong, healthy buds, make a pruning cut just above them. Repeat this process for each vine on the plant.
Pruning Group 3 clematis varieties is the opposite of pruning the other two groups. This group thrives when pruned hard since the flower buds develop on the season’s new growth. If these plants are not pruned to remove the majority of the plant, the base develops a leggy appearance that is leafless and unattractive.
Group 3 clematis should be pruned in late winter or early spring. Some gardeners prune their plants – with great success – in late fall as they go dormant for the year.
If pruning in the spring, start at the bottom of each vine and work your way up from the ground. When you come to the first pair of strong, healthy buds, make a pruning cut just above them. Then repeat the process for every vine on the clematis plant.
You can lop the entire plant off about 12-15 inches (30-38 cm) from the ground for fall pruning.
