Last updated on February 22nd, 2022
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With any type of clematis, the purpose of regular pruning is to keep the plant in check and avoid flower production becoming a mess at the top of the plant. The way these plants work is that flowers will grow off the place where the old stems stop and new stems begin, so if you fail to prune them correctly, it will keep pushing the flowers further and further out. In short, the plant gets bigger, the branches become intertwined, the flowers move further from view, and the exposed part at the base is empty.
There are three types or groups of Clematis, defined by when they produce blooms and whether those blooms are produced on old or new wood.
|Group 1||Group 2||Group 3|
|Flowering Times||Spring, on the shoots from the previous season||May and June||Late summer on growth from the current season|
|Pruning Times||Immediately after flowering from mid to late spring||Late winter and summer||Late winter through to early spring|
|Purpose||Controlling the framework and flower production||Creating and maintaining the framework, stimulating new growth, maximising flower output||Controlling framework and flower production|
Those that fall under pruning group 1 or type 1 bloom on the wood created the summer prior. They bloom early in the year after the first flowering of spring.
Group 1 Types:
- Clematis alpina
- Pamela Jackman
- Frances Rivis
- Rosy O’Grady
- White Columbine
Clematis categorised as Group 2 or type 2 are hybrid varieties that produce blooms on new wood and old wood alike. This is what produces the first and second flush of flowers in spring and summer. The first round produced in May and June are grown on the short shoots that rise out of the growth from the season prior and in some cases, varieties will flower a second time on the new growth from the current season.
Group 2 types:
- Belle of Woking
- Beauty of Worcester
- Doctor Ruppel
- Jackmanii Alba
- Show Queen
- The President
- Royal velvet
Clematis categorised as group 3 produce their flowers near the end of summer on current growth.
Group 3 Types
- C. viticella
- C. triternata
- Lady Betty Balfour
- Etiole Violette
- Polish Spirit
- Sir Trevor Lawrence
- Royal Velours
- Ernest Markham
- Princess Diana
- Duchess of Albany
When to Prune
|Group 1||Mid to late spring, immediately after flowering|
|Group 2||Late winter or early spring; February first and after the first flush of flowers in Summer|
|Group 3||Late winter through early spring|
How to Prune
For all three groups, the methods you employ for pruning mature or young plants are effectively the same.
Start by taking your sharpest set of gardening shears and disinfecting them. Use mixtures like 9 parts water to 1 part bleach to disinfect in between pruning different plants as well so that you do not accidentally transfer diseases from one plant to another.
When you are done, remove the cuttings and debris and throw them away. Leaving it on the ground beneath the plant will cultivate a haven for pests.
Regular pruning is not a requirement, but it is encouraged. You want to wait until the risk of frost has passed before you prune, typically the middle or end of spring after flowering. If you are pruning a mature plant, cut it back to the first pair of healthy buds. You can thin it out as well if the airflow is becoming a problem. To do a hard prune, make sure you cut all the way to right above the base and give it some food after and only do it once every three years. However, it’s much better to prune yearly to a specific size.
For new plants, you can cut back hard after spring, keeping the plant at 30cm above the soil level. For older plants, prune in February and remove dead branches, but do it lightly, otherwise, you will reduce the flower production. Prune after the first flush in order to get more flowers by cutting the stems below the first blooms. You can leave it unpruned and then, every 3-4 years, prune it back to 30-90 cm above the soil.
For new plants, you should cut above the first pair of leaf buds, 30cm from the ground. For mature plants, prune in February or March and cut it back to 30cm. Group 3 clematis can be pruned back very hard and benefit from doing so.