Clematis are among the most beloved climbing plants, but they can also be one of the most bewildering. With hundreds of varieties, different flowering times, and three distinct pruning groups, it’s easy to see why even experienced gardeners can feel lost. But once you understand the basics, clematis become a reliable and rewarding addition to the garden.
In this guide, we’ll break down the different types of clematis, their pruning requirements, and how to keep them thriving.
Understanding Clematis Groups and How to Prune Them
Clematis are divided into three pruning groups based on when they flower. The key to success is knowing which group your clematis belongs to, as pruning at the wrong time can result in a season without flowers.
Group 1 – Spring-Flowering Clematis
These clematis bloom in early spring on last year’s growth, meaning that heavy pruning will remove the flower buds. Instead, they should only be lightly pruned after flowering to shape them and remove dead or tangled growth.
Examples of Group 1 Clematis:
- Clematis montana – A vigorous, fast-growing variety, ideal for covering walls, fences, or pergolas. Flowers profusely in late spring with pink or white blossoms. (e.g., ‘Elizabeth’, ‘Tetrarose’, ‘Grandiflora’).
- Clematis armandii – An evergreen variety with glossy leaves and highly scented white flowers in early spring. (e.g., ‘Apple Blossom’, ‘Snowdrift’).
- Clematis alpina – Small, nodding, bell-shaped flowers that appear in early spring. (e.g., ‘Frances Rivis’, ‘Willy’, ‘Pink Flamingo’).
- Clematis macropetala – Similar to C. alpina but with more layered petals. (e.g., ‘Markham’s Pink’, ‘Blue Bird’, ‘Lagoon’).
How to Prune Group 1 Clematis:
- Prune immediately after flowering (late spring).
- Remove dead, weak, or tangled stems.
- If it’s overgrown, cut back lightly, but avoid heavy pruning.
Group 2 – Large-Flowered Summer Clematis
This group produces large, showy flowers in late spring to early summer, often with a second flush later in the season. They bloom on both old and new wood, so careful pruning is needed to encourage flowering while maintaining structure.
Examples of Group 2 Clematis:
- Clematis ‘Nelly Moser’ – Pale pink with deep pink stripes, thrives in partial shade.
- Clematis ‘The President’ – Large, rich purple flowers with a long blooming season.
- Clematis ‘Duchess of Edinburgh’ – Double white flowers with a ruffled appearance.
- Clematis ‘General Sikorski’ – Lavender-blue, free-flowering, and reliable.
- Clematis ‘Dr. Ruppel’ – Pink flowers with darker stripes and good repeat blooming.
How to Prune Group 2 Clematis:
- In late winter or early spring (February/March), cut back weak or damaged stems.
- Reduce the height of remaining stems by about one-third, trimming just above a strong pair of buds.
- After the first flush of flowers, lightly prune again to encourage reblooming in late summer.
Group 3 – Late-Flowering Clematis
These clematis bloom from mid to late summer and flower only on new growth. Unlike Group 2, these can be cut back hard each year to encourage strong, fresh growth.
Examples of Group 3 Clematis:
- Clematis viticella – Small, nodding flowers in summer, extremely reliable. (e.g., ‘Etoile Violette’, ‘Polish Spirit’, ‘Alba Luxurians’).
- Clematis texensis – Tulip-shaped flowers, often in shades of red or pink. (e.g., ‘Princess Diana’, ‘Duchess of Albany’).
- Clematis ‘Jackmanii’ – A classic, deep purple, free-flowering clematis.
- Clematis ‘Huldine’ – Elegant white flowers with a pearly sheen.
- Clematis tangutica – Yellow, lantern-like flowers followed by fluffy seed heads (e.g., ‘Golden Tiara’).
How to Prune Group 3 Clematis:
- In late winter or early spring (February/March), cut back all stems to about 30 cm (12 inches) above the ground, just above a pair of strong buds.
- This encourages fresh growth and an abundance of flowers in summer.
Common Clematis Confusions and Mistakes
Pruning Panic
Many gardeners are hesitant to prune their clematis for fear of removing flower buds. The general rule:
- Before June, don’t prune hard (Group 1 & 2).
- After June, prune hard (Group 3).
Clematis Wilt
A common fungal disease that causes sudden collapse of the stems. Prevent it by:
- Burying the crown slightly when planting.
- Avoiding damage to stems.
- Keeping plants well-ventilated.
If wilt occurs, cut back affected stems to healthy growth.
Planting Depth Confusion
Unlike most climbers, clematis should be planted deeply. Bury the crown about 5-10 cm (2-4 inches) below soil level to protect against wilt and encourage strong shoots.
Shady Feet, Sunny Tops
Clematis prefer their roots cool and shaded but their foliage in the sun.
- Mulch the base with organic matter.
- Plant low-growing perennials or shrubs around them to provide shade.
Final Thoughts
Clematis may seem complicated at first, but by understanding their pruning groups and growth habits, they become much easier to manage. Choose the right variety for your garden, follow the proper pruning method, and you’ll be rewarded with a stunning display year after year.
