Do not be afraid of pruning! You will not kill your clematis if you get it wrong, the flowers might come out late but that's about the worst that can happen.
When pruning clematis, secateurs can be rather cumbersome and their thin stems get caught in the blades which can cause the stems to get 'tugged' and damaged lower down. We have always preferred to use sharp scissors like our Barnel Clematis Pruning Scissors which are light weight and ideal for this more intricate pruning work that clematis require.
We strongly recommend that you hard prune all clematis sometime within the first year of planting for the following reasons.
1. It will encourage your clematis to put its roots out and form a strong root system.
2. It will encourage new shoots to form in the leaf axils below soil level, which were buried when planted. The more stems you have on your clematis, the more flowers you will get!
3. It will reduce the amount of foliage the young root system has to sustain.
Many nurseries will tell you to prune immediately after planting but this often means loosing flowers or the potential for flower. We recommend the following:
For Tidy Prune (Group 1) a hard prune should be carried out immediately after the first year’s flowering has finished.
For Light Prune (Group 2) a hard prune should be carried out during February or March the first year after planting.
For Hard Prune (Group 3) a hard pruned is carried out every February / March anyway.
After the first year simply follow the pruning method for established clematis below.
Following the initial hard prune, described above for the first year, these cultivars simply need a good ‘tidy up’ each year immediately after flowering has finished. Prune off unwanted growth then tie the remainder to its support.
If you wish to keep them more compact, light prune after flowering (see Light Pruning below). This will prevent the montana's from getting out of control and will help prevent others from getting a woody structure at the base. Sometimes it can cause them not to flower as well, in which case you may have to stop pruning like this and only tidy them.
Following the initial hard prune described above for the first year, light pruning should be carried out during late February or March each year.
Start at the top of the plant and reduce all stems down by about one third, to remove the 'birds nest' from the top.
Prune the remaining stems working from the top downwards looking for viable buds or shoots as in the picture to the right. These shoots may be apparent at differing heights on each stem, some as low as 6” (15cm) from the soil level and that is fine because new growth will then come at all different heights and this will help to keep the plant flowering all the way up and generally look much neater.
A complete hard prune every few years will help to rejuvenate an old, tired plant if necessary. When carrying this out we would recommend partially pruning the clematis to between thigh and waist height during late autumn or early winter. This will help the plant re-shoot low down in late winter / early spring.
Clematis from light prune group benefit from dead-heading after the early flowers have finished. Apply liquid tomato feed as recommended below, which will encourage new flowering growth to form and another good display of blooms can be enjoyed in late summer and early autumn.
Hard pruning is normally carried out during late February or March. Prune all growth back to a good set of viable buds in the leaf joints, approx. 6"- 18"(15-45cm) from soil level. If you prefer to tidy your clematis in late autumn or early winter, partial hard pruning can be carried out then. Roughly prune to 18"(45cm) and tie the remaining stems to prevent damage in a windy situation. Then in late winter or early spring a full hard prune can be carried out. It is always safer to leave a bit of extra growth on the clematis over the winter period and not prune too hard too soon.
Your herbaceous clematis can be pruned just like other herbaceous plants in the garden, however do not hard prune the Heracleifolia Group until April when the weather has improved as they over-winter much better with their old growth left intact.
Completely dead stems on some herbaceous clematis such as the Integrifolia and Diversifolia Groups can be cut to 3” (8cm) in February to March, take care to avoid nipping off the new shoots as they are emerging from the ground!
To the right is a picture of an integrifolia which has been pruned, although it could easily be mistaken for a hedgehog at first glance..!