Plants that sing during the winter should be treasured far more than those that are part of the chorus of high summer. At the start of winter, one of the moments I look forward to is seeing the first few tentative flowers on the Clematis cirrhosa that covers the woodshed. I know that by January the plant will be a blanket of creamy-yellow bells. C. cirrhosa is one of several evergreen and semi-evergreen clematis that, although they have no formal botanical grouping, all flower during the winter and early spring.
Plantsman John Hoyland chooses a list of clematis that flower in the winter and are sure to brighten your garden.
Autumn and winter cultivars
A vigorous plant that in a sheltered site can grow to 4m tall. The sweetly scented flowers are followed by silver seed heads. The main flush of flowers is during the early spring but in mild areas a few brave flowers start to appear in January.
Clematis cirrhosa ‘Wisley Cream’
First raised in the 1970s, this cultivar has proved to be a robust and undemanding plant that blooms from November to March. The flowers have a green tinge when they first open and fade to a creamy white with age.
Clematis cirrhosa var. purpurascens ‘Freckles’
Dark pink speckles on the inside of the flower glow through to the outside of the petals, giving the whole flower a pink blush. This cultivar blooms between October and February.
Clematis cirrhosa ‘Ourika Valley’
The most floriferous C. cirrhosa flowers from December to March. The tepals are longer and narrower than the species. The name refers to a part of Morocco where seed of the original plant was collected during the 1980s.
Clematis cirrhosa ‘Jingle Bells’
The first C. cirrhosa cultivar to start flowering, in the autumn. Creamy yellow buds open to flowers that fade from cream to white with age. Reputedly the hardiest C. cirrhosa, thriving even in cold parts of the North.
Clematis cirrhosa var. balearica
From the island of Minorca, this clematis is covered with speckled, lemon-scented bells from November to March. In very cold weather the ferny foliage turns bronze and purple. Grown in Britain since the 18th century, it received an RHS Award of Garden Merit in 1993.
Late winter cultivars
This New Zealand hybrid bears small buds like green berries for weeks. They begin to flower, sparsely, from January, then profusely from March to May. The leaves are fern-like and grow from thin, wiry stems. Up to 1m tall.
Clematisx cartmanii ‘Avalanche’
This lives up to its name, with masses of white flowers, up to 6cm across, from February to April. The dark leaves are like parsley and the purple stems are a bonus after flowering. It holds an RHS Award of Garden Merit.
Clematis paniculata var. lobata
The flowers are slightly larger than the species, but just as sweetly scented. The new leaves have roughly toothed edges, but this disappears as the plant matures. Flowers from January, and more profusely from early spring.
Clematis ‘Early Sensation’
The buds of this plant dangle but turn up as the flowers open, from February to April. The base of the petals is apple green, making a crisp contrast with the dark, waxy foliage. This non-clinging climber grows up to 2m tall.
Clematis x cartmanii ‘Joe’
Fat buds, full of promise, start to appear in January and grow like bunches of grapes for several weeks until opening. The flowers are as close as you can get to a buttercup, a relative in the Ranunculaceae family.
Clematis ‘Fragrant Oberon’
Another recent hybrid of two New Zealand species, bred in the early 1990s but only available for the last year or so. It has strongly perfumed flowers, each about 3cm wide, from February to May. Up to about 1.5m tall.
Big, leathery leaves emerge copper-coloured, maturing to a shiny green. Clusters of pink-tinged buds open to white flowers from February to May. The perfume from hundreds of flowers on mature plants can be powerful.
Clematis armandii ‘Snowdrift’
Just as vigorous and sweetly scented as the species, this cultivar flowers at the same time, but the tepals are narrow and slightly twisted, so they look star-like. Best planted in a south-facing, sunny situation away from cold winds.
This tender species is usually in flower in December and is as jolly as any Christmas decoration. The green, bean-shaped buds open to reveal flowers with dangling purple stamens. In most parts of the country this species needs the comfort of a cold greenhouse or conservatory.
Clematis ‘Lunar Lass’
Another tender New Zealand hybrid, this needs winter protection so is best grown in a conservatory or cold glasshouse. It’s a compact, scrambling plant with stems 60cm long and bears strongly citrus-scented flowers from February to April.
Tips on growing winter clematis
Clematis x cartmanii and associated hybrids were originally thought too tender to grow outdoors in Britain. In fact they will thrive in sheltered places that do not drop below -5°C during the winter, as long as they are protected from cold, drying winds. In colder areas, grow in pots in cool greenhouses or conservatories.
Cold winds are also the enemy of Clematis armandii so choose a sheltered spot in sun or part-shade.
In general clematis prefer moist conditions but C. cirrhosa must be kept dry, especially during the winter. An ideal place to plant it is on a south or west-facing house wall where the eaves of the roof protect the soil from heavy downpours.
Clematis need rich, moist soil with a cool root-run, so plant low-growing shrubs or perennials close to the base to shade the soil. C. armandii needs to be well fed, so apply a generous mulch of compost every autumn.
C. cirrhosa will need support at first by tying the stems in to 1m canes. As it becomes established it will twine itself around wires, posts or trellis. Clematis x cartmanii hybrids are not twining plants so they are unable to support themselves when grown as climbers. They can be left to sprawl along the ground or to flow over the edge of pots.
Pruning winter clematis to control growth
C. armandii and C. cirrhosa are vigorous plants that need regular pruning to be kept under control.
- They flower on growth made the previous year, so wait until they have finished flowering before doing any pruning.
- Cut back growth to about 1m below the area you want the plant to cover.
- After three or four years both C. armandii and C. cirrhosa may develop dense, woody ‘bird nest’ growth. Cut back about one third of the plant to the base and repeat the process on the other two thirds in subsequent years.
To stimulate flowering
Clematis ‘Early Sensation’, and the cartmanii hybrids produce so many flowers that they often exhaust themselves and generate little in the way of new growth. To keep the plants vigorous and healthy, prune them in two stages:
- Trim them immediately after the flowers have finished, to remove the dying flower heads and prevent any energy being lost in seed production.
- At the end of May, cut the whole plant back to about 50cm from the soil, to encourage new growth and prevent the plant from becoming bare and woody at the base.
To thicken growth
C. paniculata tends to be spindly, but looks better with bushy growth.
- For a few years after planting, cut back to 60cm from the ground.
- Once it has become bushy, allow it to grow into the size you want and then trim it back each year after flowering.
County Park Nursery
Priorswood Clematis Nursery
Words John Hoyland, photographs Jason Ingram