Clematis is the queen of climbers, adding bold colour to pergolas, walls and trees. Choose from giant star-shaped blooms, showy double flowers or elegant, pendant-like blooms, and varieties that flower in winter, spring, summer or autumn.
Clematis are popular climbing plants that produce masses of flowers. There are hundreds of clematis species and hybrids, which vary in when they flower, how large they grow, and the shape, size and colour of the flowers. Clematis are perennial plants, which means they come back year after year. While most are deciduous, a number of evergreen clematis plants keep their leaves all year round.
Where to plant clematis
Clematis like cool shade around their roots and sun on their leaves. As these specific conditions rarely occur naturally, you may have to get creative. Planting a shallow-rooted perennial around the base of the clematis can help shade the lower part of the plant in warmer months. A good layer of mulch can also help keep the roots cool. Most clematis enjoy full sun, but there are a few varieties that do better in partial shade, such as ‘Nelly Moser’ and Clematis alpina.
Some clematis can be grown in pots, but you’ll need to select a less vigorous variety. Climbing clematis require some kind of support or structure for the plant to grow up. Trellises and pergolas can work well for smaller varieties, whereas rampant climbers will happily cover large walls or wind their way up a mature tree.
When to plant clematis
It’s best to plant clematis in spring or autumn, when the soil is warm and moist. You can plant container-grown clematis in summer, just make sure you plant it in moist soil and water well during dry spells.
How to plant clematis
Clematis are hungry plants that like moist, fertile soil. Dig a bucketful of compost or well-rotted manure into the ground before planting your clematis plant. The planting depth depends on the variety of clematis:
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Large-flowering hybrids, which flower in early and late summer, should be planted with the top of the root ball 5–7 cm below the surface, as this encourages underground shoots and multiple stems.
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Herbaceous clematis, winter and spring-flowering clematis and late summer and autumn-flowering species clematis should be planted with the root ball at or just below the surface of the soil.
If you’re planting your clematis next to a wall or fence, make sure the hole is at least 30 cm away from the base. If it’s near a tree or large shrub, it needs to be about a metre away from the trunk – you can lean a support cane toward the tree or use wire for the clematis to scramble up.
Once you’ve positioned your clematis plant, backfill the hole and water it well. Pruning new clematis plants immediately after planting helps encourage them to produce multiple stems. Cut back to above a strong pair of buds, around 30 cm above the ground, in the first spring after planting.
Growing clematis in pots
When growing clematis plants in pots, it’s important to choose a large container with enough space for the roots to grow – it should be at least 45 cm wide and deep. Add crocks or gravel to the bottom for drainage and fill it with loam-based compost, such as John Innes No. 3 or a multipurpose compost with John Innes.
After planting and watering your clematis, you need to take steps to keep the roots cool. If you’ve planted a sun-loving variety, this may mean planting bedding plants or other low-growing plants around the clematis or adding a layer of pebbles. You could also position the pot so the base is shaded by surrounding plants.
Clematis don’t like to dry out, so you’ll need to keep a close eye on clematis in pots and water them regularly.
How to look after clematis
Clematis isn’t one of those plants you can put in the ground and forget about. They are thirsty plants and struggle in drought conditions, particularly while they’re getting established. Water new plants regularly for the first couple of growing seasons to prevent the soil from drying out. Clematis grown in containers may need watering daily from late spring to early autumn, depending on how much rain has been able to reach the roots.
You can help your clematis grow and flower by feeding it. Apply a potassium-rich fertiliser around the base of plants in late winter or early spring, and then add a layer of mulch. Container-grown clematis will benefit from monthly feeds of liquid fertiliser.
Tying in clematis
A clematis uses its leaf stems to climb, wrapping them around thin branches, canes, twine or wire. To encourage this, make sure any supports you put in place aren’t too wide for the leaf stems to wrap around. If you’re training it up a trellis with wide slats, consider adding support twice or trellis netting to help the clematis get established.
You can tie in stems using twine or foam twist ties, but bear in mind that the stems are delicate, so don’t tie them in too tightly.
When to prune clematis
Clematis pruning isn’t difficult, as long as you know which group it belongs to. Clematis plants are divided into three groups, with each group having different pruning requirements. If you’ve inherited a plant and you’re not sure when to prune your clematis, keep an eye on when it flowers. If it flowers before June, don’t prune it. If it flowers later, then prune in February.
Clematis pruning group 1
Group 1 clematis plants flower in winter and spring on shoots from the previous year. Established plants don’t need regular pruning, but if you want to trim long branches or remove dead or diseased wood, the best time to do this is immediately after flowering. For winter-flowering clematis, make sure the risk of frost has passed before pruning.
Clematis pruning group 2
Group 2 clematis consist of large-flowered varieties that flower in late spring and early summer. They also flower on the previous year’s growth, but should be lightly pruned in February, before new growth emerges. When trimming clematis in this group, your aim is to keep much of the old wood as a framework, while encouraging new shoots to maximise flowering. Remove any damaged or weak stems and trim other stems to just above the highest strong pair of buds. If you cut back any further than this, you’ll lose spring flowers.
Some group 3 clematis bloom for a second period in late summer. To encourage this, prune back stems to a large bud or strong side shoot once the first lot of flowers has faded.
Clematis pruning group 3
Group 3 clematis plants flower in mid or late summer on new growth. Herbaceous clematis also fall into this group. You should prune group 3 clematis in late winter or early spring, when buds are just beginning to show signs of growth. Cut back all stems to the lowest pair of strong, healthy buds – this should be about 20–30 cm above ground level.
You can prune herbaceous clematis to ground level in early spring or late autumn.
Renovating clematis plants
If you have a group 1 or 2 clematis that’s overgrown or has got top-heavy, you can carry out a hard pruning. For group 1 clematis, you can cut stems back nearly to the ground after flowering, and for group 2 clematis, you should follow the guidance for pruning group 3 clematis in late winter. It may take a year or two for clematis to recover, so it’s best to only carry out this type of pruning every three or four years.
How to propagate clematis
You can propagate clematis by taking cuttings, collecting and sowing seeds, and layering – a process where you loop stems in and out of the soil and leave them for a couple of years until the buried sections grow roots. The best method varies depending on the type of clematis, but most people try taking clematis cuttings first.
How to take a clematis cutting
You can propagate clematis by taking softwood cuttings (in April or May) or semi-ripe cuttings (from spring through to late summer). Clematis can be tricky to propagate, so it’s worth taking more cuttings than you need in case they don’t all make it.
You want to take internodal cuttings (“internodal” meaning between two nodes) for clematis. The nodes are the points where the leaves attach to the stem. Cut each section so you have about an inch of stem above the node and a longer section below – this is the section you’ll be planting, so the exact length will depend on the depth of your pot. Use a sharp knife to trim the stems to avoid damage. As cuttings lose a lot of water through their leaves, you want to remove excess leaves, leaving just one for photosynthesis.
You can plant multiple cuttings in one pot. Fill the pot with wetted cutting compost, which you can make by mixing equal amounts of potting compost and perlite or sharp sand. Poke a hole for each cutting and gently insert it into the compost. Cover the container with a clear plastic bag, to keep moist air around the cuttings, and leave it somewhere warm, out of direct sunlight, until the cuttings have rooted. This may take a couple of months.
Common problems
There are a few problems to look out for when growing clematis:
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Environmental conditions are often the primary cause of wilting and flowering issues. Clematis plants struggle when their roots get hot and dry, so make sure they have fertile soil and water your plant during dry spells. They can also be quite delicate, and stems are prone to damage in exposed locations.
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Clematis wilt is a fungal disease that causes large-flowered varieties to suddenly wilt and die. Leaf stalks and stems will also turn black. If you suspect your plant is infected, remove and destroy the affected stems.
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Earwigs, capsid bugs, slugs, snails, and rabbits may feed on clematis leaves. In most cases, damage is cosmetic, but you may want to protect young plants, which are more at risk.
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Green petal is a condition induced by cold temperatures. It affects the colours of early flowers, which may be green-tinged or fail to colour in the normal way. Later flowers should be unaffected. If the flowers look distorted and symptoms continue, the plant likely has green flower disease and should be destroyed.
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Clematis slime flux is a bacterial issue that causes a foul-smelling froth or slime to ooze from the stem. It’s hard to prevent, other than avoiding anything that could damage the stem, but if you remove the affected stem, you may be able to save the plant.
Our favourite varieties of clematis
It’s hard to choose a favourite clematis, as there are so many varieties to choose from. When selecting a plant, think about its location (specifically how much sun it will get), how tall you want it to grow and when you want it to flower.
Clematis montana ‘Rubens’ is a much-loved, vigorous climbing clematis that produces masses of fragrant pink flowers in late spring. It needs space to grow, making it an ideal choice for covering a wall, a large trellis or an unsightly shed.
Clematis ‘Nelly Moser’ is a popular clematis for shade, as too much sun can bleach its striking pink-striped petals. It’s a twice-flowering variety, blooming in early summer and again in autumn.
Clematis cirrhosa ‘Freckles’ blooms in the depths of winter, adding a burst of colour to your garden between December and February. It’s an evergreen clematis with pale flowers scattered with burgundy “freckles”.
Clematis armandii is another evergreen clematis with glossy, dark green leaves and star-shaped white flowers. It’s fast-growing and is best trained across a pergola, along a fence or up a wall.
Clematis alpina is a gorgeous purple clematis that flowers in late spring and early summer. This low-maintenance clematis grows well in partial shade and is a good choice for cottage or woodland gardens.
FAQ
When should you prune clematis?
Group 1 clematis (winter and spring flowering) don’t require pruning, but you can remove any damaged or weak stems immediately after flowering. Group 2 clematis (large-flowered clematis that flower in late spring and early summer) should be given a light trim in February – cut to just above the highest pair of strong buds. Group 3 clematis (which flower in mid to late summer) need hard pruning in late winter. Cut back stems to a pair of strong buds around 30 cm above the soil.
When should you plant clematis?
Clematis is best planted in late spring or early autumn. If you’re planting clematis plants in the summer, make sure you water them in well. Whenever you plant it, a clematis usually needs watering during the first couple of growing seasons, particularly during dry weather.
How do I take cuttings from clematis?
You can take softwood or semi-ripe cuttings from a clematis. Cut a section of stem around a single node, making the cuts about an inch above the node and 4–6 inches below. Remove extra leaves (leave just one on the cutting) and place cuttings in a pot of cutting compost. Cover the pot with a plastic bag and place it somewhere warm, but out of direct sunlight, until the cuttings have rooted.
Can you grow clematis in a pot?
Yes, you can grow clematis in pots, but they require a bit more care and attention, particularly when it comes to watering. If you take steps to keep the roots of your plant cool, for example, by creating shade or top-dressing with pebbles, and water and feed it throughout the summer, your clematis will thrive.
Do you cut back clematis every year?
This depends on the type of clematis. Clematis in pruning group 3 (which flower in mid to late summer) should be cut back to near the ground annually in late winter or early spring. Other clematis don’t require such hard pruning, though if a plant has become top-heavy or overgrown, you may choose to cut it back to near ground level. This should only be done every three or four years for group 1 and 2 clematis.
