How to prune clematis
Even some of the most experienced gardeners worry about how to prune their clematis. However, it is quite easy to determine the best method to use. The flowering periods of clematis are divided into three groups, each with their own regime.
|Clematis Pruning Group||Flowering Period|
|Group 1||Early to Mid-Spring|
|Group 2||Late Spring to Early Summer|
|Group 3||Mid to Late Summer|
Pruning Group 1: Early Spring Bloomers
Includes varieties such as the popular Clematis montana and Clematis armandii. They produce flowers in early spring from the new shoots that have grown from the previous year. They do not require regular pruning and can be maintained by simply removing the flowers once they have faded.
Some plants may require pruning for shape or if they have outgrown their original space. To make them thinner, cut back any tangled or damaged shoots to healthy buds after they have finished flowering in late spring. The amount that you will need to remove will depend on how vigorous your variety is. Clematis montana can almost be cut back to the ground, but some varieties such as Clematis armandii are reluctant to flower again if cut back too far. For older plants that require complete rejuvenation, more severe pruning may be needed. In this case, plants can be cut back to 6 inches from their base after flowering. This more thorough method should only be carried out once every 3 years. For gardeners who wish to be extra careful, this kind of pruning can be carried out gradually over those years, although it will reduce flowering for an extended period.
Pruning Group 2: Late Spring/Early Summer Bloomers
This group involves clematis that produce large flowers in May or June. They flower mostly on older stems, but can also flower on new shoots later in the season. This group includes varieties such as Clematis ‘Nelly Moser’ and Clematis ‘Snow Queen’. Pruning of this group is needed to stimulate new growth and encourage a longer flowering season. Pruning should be carried out during late winter or early spring and again after the first bunch of flowers in early summer.
In late winter, remove any dead or weak shoots, then check each healthy stem from the top-down and cut back to the first pair of strong buds from the top of the stem. After the first bunch of flowers, cut back some of the stems to strong buds or side shoots just below a flower. This will encourage a second flush of flowers in late summer. It is important to do this even with young clematis because if you allow shoots to grow without regular pruning you will be left with long thin shoots that will only flower at the very ends. Cutting back to healthy buds on multiple stems will encourage even distribution of the plant's energy, resulting in strong dense coverage.
Avoid irregular, heavy pruning, as this will reduce flowering the following summer. If plants have outgrown their space and require heavy pruning, do this gradually over a number of seasons to avoid damaging your plant. If carrying out extensive pruning after the first flowers of early summer, you are unlikely to see any flowers again that season, but your clematis should flower again the following year.
With the use of a trellis or wires, you can provide new stems with support during the summer. This will allow your clematis to provide even coverage and prevent tangled shoots, reducing the need for heavy pruning in the future. Another option for Group 2 is to prune heavily every few years, just before the flowering season, and completely avoid pruning in between. This is often seen as the easiest process but will prevent any early summer flowering on the season that you prune.
Pruning Group 3: Mid - Late Summer Bloomers
This group of clematis flower in mid and late summer. They flower from new growth produced early in the year. If left unpruned, new flower-producing shoots will grow from the previous year, with flowers being produced only at the tops of the new shoots. Within this group, you can find varieties such as Clematis ‘Ville De Lyon’ and Clematis ‘Ernest Markham’. Pruning should be completed as soon as you see any signs of new growth. This will usually occur around late winter or early spring. Cut back to the lowest healthy buds on each stem. This will ensure that flowers will be produced over the full length of the plant.