Clematis plants are a beauty to behold in the garden, with their stunning flowers adorning a broad mass of vines. While their creeping growth makes some homeowners think they never need pruning, some need regular pruning to encourage strong vine growth and beautiful flushes of blooms. Pruning also keeps plants from becoming a mess of tangled stems.
Pruning clematis isn’t as easy as going outside and lopping off whatever vines you want to go. It’s essential to prune them correctly. If they are pruned improperly, you can unknowingly cause your plant to stop flowering completely. So, let’s talk about how to prune clematis!
Clematis Pruning Groups
Clematis species are classified into three groups (Group 1, 2, and 3), depending on the timing of their flowering season. In turn, this helps determine if the clematis bloom on new growth or old vines. These blooming characteristics dictate when and how to prune your plant, resulting in the best growth and blossoms.
- Group 1 varieties are spring bloomers.
- Group 2 varieties are mid-season bloomers (late spring or early summer) and can be repeat bloomers.
- Group 3 varieties are late summer or fall bloomers (July, August, or September).
Group 1: Early Spring Bloomers
Often called “Group A” or “Type A,” this group of cultivars tends to be larger plants that bloom with big blossoms very early in the growing season. Their ability to flower so early in the season means the flower buds were formed during the previous year, so they bloom on old wood.
Group 1 includes Clematis alpina, Clematis armandii, Clematis cirrhosa, Clematis macropetala, and Clematis montana. Popular cultivars include:
- ‘Franci Rivis’
- ‘White Columbine’
- ‘Apple Blossom’
- ‘Jacqueline du Pré’
- ‘Pamela Jackman’
- ‘Blue Bird’
- ‘White Swan’
How to Prune Group 1
Since Group 1 flowers on the plant’s old growth, the general rule when pruning them is to avoid pruning unless you are trying to control their growth or maintain the plant’s shape. Severely pruning these plants removes all developed buds, resulting in a plant that won’t flower. If you decide to prune them, do so just after flowering.
When pruning this type, trim back no more than one-third of the plant as they do not like severe pruning. Pruning them early in the season encourages new growth that develops buds for the following spring.
Group 2: Repeat Bloomers
Also known as “Group B” or “Type B,” Group 2 blooms later than Group 1 and earlier than Group 3. The first flush of flowers opens in late May or early June, with a second bloom erupting in late summer. Buds develop on a combination of old clematis vines and new wood.
Group 2 includes Clematis florida and Clematis patens. Some of the most common varieties are:
- ‘Bees’ Jubilee’
- ‘Nelly Moser’
- ‘The President’
- ‘Capitaine Thuilleaux’
- ‘Duchess of Edinburgh’
How to Prune Group 2
Plants in group 2 are a cross of the other two groups. Some of their flower buds develop on old stems from the previous year and some form on the current year’s new vine growth. Just as growth starts in the spring, light pruning is best with this type unless the plant has overgrown its space.
Depending on your climate, plan on pruning this group in February or early March, or perhaps even April. It is best to wait until the plant’s flower buds start turning green and begin swelling, making them easy to see.
Locate the end of each vine and work your way down until you reach the first pair of healthy buds. Make a pruning cut just above these buds, repeating this method for each vine on the plant.
Group 3: Summer or Fall Bloomers
Group 3 bloom the latest in the season of the groups, blooming in late summer or early fall to give your garden a later-season pop of color. This category blooms on the current season’s new shoots. The one drawback to this group is the new shoots require you to train them every year, but it’s worthwhile.
Common plants in group three are Clematis orientalis, Clematis tangutica, Clematis texensis, Clematis viticellas, and hybrids. Common cultivars include:
- ‘Polish Spirit’
- ‘Alba Plena’
- ‘Duchess of Albany’
- ‘Ernest Markham’
- ‘Gipsy Queen’
- ‘Comtesse de Bouchaud’
- ‘Purpurea Plena Elegans’
- ‘Rouge Cardinal’
- ‘Mme. Julia Correvon’
- ‘Warszawska Nike’
- ‘Margot Koster’
- ‘Lady Betty Balfour’
How to Prune Group 3
The pruning guidelines for Group 3 cultivars are the opposite of the other two. Their flower buds develop on the season’s new growth, so plants thrive when given a hard prune before active growth starts. If these plants are not pruned to remove most of the plant, the base develops weak stems and a leggy appearance that is leafless and unattractive.
In February, you should prune group 3 plants in Southern growing zones and in early March if you live in the North. Some gardeners prune their plants – with great success – in late fall as they go dormant for the year.
- If pruning in the late winter or early spring, start at the bottom of each vine and work your way up from the base of the plant. 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 plant.
- If pruning in the fall, cut the entire plant off about 12-15” above ground level. Plants will grow back next spring.
- Never prune first-year growth. Wait until the second growing season to prune your vines to give you a better understanding of when it blooms and what wood to prune.
- Deadhead spent flowers from the vines immediately after they fade to encourage a second round of blooms.
- Regardless of your pruning type, always remove any dead or damaged stems. They can be pruned at any time during the season to keep your plant looking its best.
- Always clean and disinfect your pruning shears before and after working to prevent the spread of disease from one plant to another.
- When pruning plants to tidy up their shape, periodically step back to assess the overall form and your progress.