Climbing clematis are wonderfully showy plants that produce huge blooms over a long period. They grow well in borders and patio pots, climbing up pergolas, obelisks and trellis, adding valuable height to the garden.
Give plants a weekly feed with tomato fertiliser in summer, and deadhead to prolong flowering. If growing clematis in a pot, choose a large container and repot every two years into John Innes No. 3 compost with added slow-release fertiliser. Mulch the surface to protect the roots from hot sun.
Summer-flowering clematis need pruning annually. If they flower in May/June (Group 2 clematis), trim them at the end of June, then cut back to strong buds in February/March. Those that flower in late summer are classed as Group 3 clematis, and need to be pruned as set out in our advice on winter-pruning clematis.
When buying clematis, choose plants that are at least two years old (in 2-3 litre pots) to ensure the roots are well developed before planting.
Discover 10 pretty summer clematis to grow, below.
Clematis ‘Warszawska Nike’
This clematis has velvety purple flowers in late spring to early summer, and autumn. Grows to a height of 3m. Pruning Group 3.
Clematis ‘Night Veil’
‘Night Veil’ bears small, semi-nodding flowers with a redder central bar on each petal and white filaments with dark purple anthers. It grows to 250cm and is perfect for training up obelisks. Pruning Group 3.
Clematis florida ‘Alba Plena’
Double, greenish white flowers appear from June to October. Plant this variety in full sun, to achieve long stems of up to two metres. ‘Alba Plena’ can be grown in a container. Pruning Group 3.
Clematis ‘Etoile Violette’
With an abundance of rich, deep purple flowers throughout summer, ‘Etoile Violette’ is ideal for growing through an evergreen or spring-flowering shrub. For best results, grow it against a bright background. ‘Etoile Violette’ grows to 4m. Pruning Group 3.
The large blooms are prolific in May and June and may then disappear until September. To encourage more, cut the stems back in the July lull. ‘Kingfisher’ is not suitable for growing in deep shade. Pruning Group 2.
Suitable for a container, ‘Picardy’ rewards with lots of relatively small, but prolific flowers. These are occasionally semi-double. Intensely dark new flowers become paler with age. Pruning Group 3.
Clematis ‘Princess Diana’
This texensis type of clematis flowers from June to September, with vibrant pink long slim tepals, set off by bright green foliage. One of the tallest of these clematis, ‘Princess Diana’ will reach a height of 3m. Plant it in sun or partial shade. Pruning Group 3.
This viticella clematis tolerates shade and grows to a height of 3.5m. Pruning Group 3.
Clematis viticella ‘Jolly Jake’
Prune this tough, robust violet-burgundy variety down to 20cm in February, to benefit from lots of flowers on new growth, or allow it to scramble through a trellis and flower on branch ends. Pruning Group 3.
A vigorous grower, ‘Chatsworth’ is best suited to growing up a sturdy obelisk in a large herbaceous border, or being trained to grow through a tree or shrub. Pruning Group 3.
Thanks to the following clematis specialists who provided information on the plants in this feature:
Planting your clematis
As a rule most clematis prefer to be planted in garden soil rather than in containers. Clematis benefit from being planted deeper than they were in the purchase pot. Plant about 5cm deeper and new shoots will be encouraged.
Clematis pruning groups explained
- Pruning Group 1 – no pruning required. Can be pruned to tidy them up which is carried out straight after flowering
- Pruning Group 2 – some pruning required. Prune in February/March by removing dead, damaged and diseased growth. Trim other stems to just above the strongest and highest pair of buds
- Pruning Group 3 – hard pruning required. Cut right back in spring before growth begins, pruning to just above a healthy bud, about 30cm from the soil