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How to grow clematis and the best varieties
Clematis are among the most popular climbing plants. Discover our recommended varieties, plus tips on where and how to grow them
You can grow clematis in the ground or in containers, and by planting varieties from the diverse groups that flower at different times of the year, you could be enjoying their blooms for many months.
The Which? Gardening experts grew and compared 24 early to mid-summer-flowering clematis varieties, 11 winter-flowering ones, 10 patio ones for pots, 25 late-summer flowering ones and 22 spring-flowering ones, to help you find the best ones for your garden with beautiful flowers over a long period.
Our experts share our tried-and-tested varieties, advice about where to grow clematis, including in pots, plus how and when to prune.
Key facts
Plant type - Hardy climber
Position -Sun or partial shade with shaded roots
Soil -Well-drained and fertile
How to grow clematis: month by month
January
February
March
April
May
June
Prune group two and three
Prune group two and three/Plant
Plant
Prune group one/Plant
July
August
September
October
November
December
Plant
Plant
Planting clematis
Preferably buy plants in 2-3L pots and plant at any time of year when the ground is workable, although the dry summer months aren’t ideal. Provide shade for the roots so they stay cool. Plant them so the root ball is 5-7.5cm under the soil. Water regularly until they’re well established.
Can you grow clematis in a pot?
Yes, you can. See the best patio clematis varieties below.
Use a large pot to give roots room to grow, roughly 45cm in diameter and depth.
Avoid clematis wilt by planting deeply so the top of the roots are below soil level.
Buy a good-quality obelisk that will support your plant for a number of years; we found that cheap wicker obelisks soon broke. Ensure the diameter will fit your pot.
Topdress with fresh compost and controlled-release feed annually.
Water regularly; daily during hot weather.
Most varieties will grow better if you site them away from potential cold winds. Strong sun can fade flower colours. Move the pot so the plant gets some midday shade if necessary.
OVERALL RATING Ignores price and is based on flower coverage 30% , flower impact 30%, flower duration 20%, seedhead attractiveness 15%, pest and disease resistance 5%.
Early to mid-summer-flowering clematis
Variety name
Overall rating
Flower duration
Flower impact
Flower coverage
Plant shape
Pest and disease resistance
'Andromeda'
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Overall rating ignores price and is based on: flower duration 20%, flower impact 20%, flower coverage 20%, plant shape 20%, pest and disease resistance 20%, using ratings from the third year of the trial. Plant shape ratings are based on the vigour of the plants and how well they covered their support.
Mid to late-summer-flowering clematis
Variety name
Overall rating
Flowering duration
Flower impact
Flower coverage
Vigour
Pest and disease resistance
'Abundance'
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OVERALL RATING Ignores price and is based on: flower duration 25%, flower impact 20%, flower coverage 20%, vigour 20%, pest and disease resistance 15%, using ratings from the second year of the trial. Vigour ratings are based on the vigour of the plants and how well they covered their support. Height and spread given for the second year of growth.
Patio clematis for growing in a pot
Variety name
Overall rating
Flowering duration (North)
Flowering duration (South)
Flower impact
Flower coverage
Foliage
Suitability for pots
Pest and disease resistance
'Bijou'
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OVERALL RATING Ignores price and is based on: flowering duration in the north 25%, flowering duration in the south 25%, flower impact 20%, flower coverage 15%, foliage 5%, suitability for pots 5%, pest and disease resistance 5%.
Winter-flowering clematis
Variety name
Overall rating
Flowering duration
Flower impact
Flower position
Foliage impact
Vigour
Pest and disease resistance
Hardiness
'Advent Bells'
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OVERALL RATING Ignores price and is based on: flowering duration 55%, hardiiness 20%, flowering impact 15%, flower position (if the flowers were only at the top of the plant or all over, and if they were hidden by foliage) 5%, foliage impact 5%, vigour 5%, pest and disease resistance 5%.
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Growing clematis
Feeding and watering
In fertile soil they might not need feeding. In poor soil use a general fertiliser, such as Growmore, in spring. Mulch annually with 5-7.5cm of well-rotted compost. Established clematis shouldn’t need watering unless the soil is very dry.
Clematis are divided into groups according to when they're pruned. Check the label when you buy your plant and make a note of the group.
Group one These flower early in the year on shoots produced the previous season. Trim back after flowering and tie in stems as needed. Cut back by around half to renovate if needed.
Group two These are large-flowered varieties that flower in May and June. Dead or weak stems can be removed or shortened before flowering in February or March. After flowering, some stems can be cut back by half to sideshoots or strong buds, to encourage new growth and a second flush.
Group three These bloom in mid- to late summer. In February or March, cut all stems to a pair of healthy buds around 20-30cm from the ground.
These can be done several ways using both softwood and semi-ripe material (for example, gets firm at the base in late summer); they all root easily. Taking internodal cuttings of the current-season growth will give you good results.
1. Pick out healthy growth and look for strong buds between the leaf and the stem; weaker buds might not root as well.
2. Trim the stem to about 5-7cm from below the point where the leaf joins the stem.
3. Shorten the top to just above where the leaf joins the stem, just leaving a single growing point with a pair of leaves either side of that point.
4. Trim the leaves by half to reduce water loss.
5. Insert the cuttings into a Best Buy compost for raising young plants right up to where the leaf joins the stem. Leave lots of space between the cuttings, as clematis tend to rot off if they touch. Label, water and put in a coldframe, greenhouse or propagator. Clematis root better in humid conditions, so if you’re using a windowsill, cover your pot with a clear plastic bag.
6. Pot on individually once rooted.
Are clematis poisonous to dogs and cats?
Clematis aren't generally considered poisonous to dogs, although according to The Dogs Trust, C. armandii can potentially cause dermatitis, gastro-intestinal and nervous-system problems, so you may wish to avoid it. In cats, clematis can cause skin irritation, so discourage yours from rubbing on them.
Common clematis problems
Clematis wilt
This is a fungal disease that causes the whole plant to wilt. Planting deeply will mean that you can cut back the whole plant and it should regrow from the base. Sometimes the cause isn't clematis wilt, but actually physical damage, such as slugs nibbling the stems at the base.
Greenfly
Greenfly can quickly build up and cause poor growth by sucking the plant’s sap. Treat by squishing any colonies by hand.
Green petal occurs if there's a late cold snap in the spring, while the buds of the plants are forming. It causes some of the petals to become bright green and distorted. Although it might be unsightly, there are no detrimental effects to the plant.
Slime flux
This is a bacterial problem that can cause the plant to collapse and horrible ooze to come out of the base. Cut back the whole plant and it should resprout from the base.