What is clematis wilt and how do I stop it?

Clematis wilt is a fungal disease causing sudden blackening and collapse of stems. Planting deeply, 5-8cm below the original soil level, helps the plant regrow from dormant buds if it strikes. Remove and destroy affected stems promptly.

How do I know which pruning group my clematis is in?

Check the plant label or supplier information, as pruning group is usually stated there. Early spring flowerers are typically Group 1, large-flowered summer hybrids are Group 2, and late-summer flowering varieties are usually Group 3.

Can clematis grow in shade?

Most clematis flower best with their top growth in sun, though some varieties such as Clematis alpina tolerate partial shade. The roots should always be kept cool and shaded regardless of variety.

When should I plant clematis?

Container-grown clematis can be planted at almost any time of year, but autumn or spring are ideal as the soil is moist and temperatures are mild, helping roots establish before extremes of weather.

Why is my clematis not flowering?

Poor flowering is often due to incorrect pruning for the group, insufficient sunlight on the top growth, or lack of feed. Check the pruning group and ensure a potassium-rich feed is applied in spring.

Do all clematis need pruning every year?

Group 1 varieties need minimal pruning, mainly to control size after flowering. Group 2 and Group 3 varieties benefit from annual pruning in late winter to maintain vigour and encourage flowering.

How to Grow Clematis: UK Care Guide

Clematis is a versatile flowering climber that thrives in UK gardens when given a cool, shaded root run and a sunny top. Success depends on choosing the right variety for your pruning group, planting deeply to guard against clematis wilt, and providing sturdy support such as trellis, wires or an obelisk.

Key takeaways

Plant clematis 5-8cm deeper than the pot to encourage resilient buds below soil level.
Identify the pruning group (1, 2 or 3) before cutting, as timing differs for each.
Keep roots cool and shaded with paving slabs or low planting, while the top grows into sun.
Clematis wilt affects large-flowered hybrids most; deep planting helps plants recover.
Feed with a potassium-rich fertiliser in spring to support strong flowering.

Attribute	Detail
Botanical name	Clematis spp.
Plant type	Deciduous or evergreen climber
Height & spread	Up to 3-6m x 1-2m depending on variety
Hardiness	RHS H5-H7 (fully hardy in most of the UK)
Position	Full sun to partial shade, shaded roots
Soil	Fertile, humus-rich, well-drained, neutral to alkaline
Flowering/interest period	Spring to autumn depending on group
Difficulty	Moderate

Choosing varieties

Selecting the right cultivar makes pruning and care far simpler. Below are reliable choices available from UK nurseries, covering all three pruning groups.

Variety	Pruning group	Flowers	Notes
Clematis armandii	Group 1	White, scented, early spring	Evergreen, needs a sheltered wall
Clematis montana 'Elizabeth'	Group 1	Pale pink, late spring	Vigorous, good for covering fences
Clematis 'Nelly Moser'	Group 2	Pale pink with darker stripe, early/late summer	Fades in strong sun
Clematis 'The President'	Group 2	Deep purple-blue	Repeat flowering, reliable
Clematis 'Etoile Violette'	Group 3	Violet-purple, summer	Vigorous, great for pergolas
Clematis viticella 'Polish Spirit'	Group 3	Purple-blue, late summer	Resistant to wilt

Supports and where to plant

Clematis climb by twisting their leaf stalks around thin supports, so trellis, wires spaced 20-30cm apart, or netting work better than smooth poles. Choose a spot where roots stay cool and shaded, ideally behind a low shrub or paving slab, with the top growth able to reach sunlight. Walls, obelisks, arches and shrubs for scrambling through are all suitable, but avoid exposed, windy sites for large-flowered hybrids. See our how-to guides for support installation tips.

How to plant clematis

Choose a planting site with sun on the top growth and shade at the base.
Dig a hole twice the width of the root ball and enrich with well-rotted compost.
Soak the pot thoroughly before planting.
Position the plant 5-8cm deeper than it sat in its pot, to protect against wilt.
Backfill, firm gently and water well.
Add a mulch or slate chippings to keep roots cool, avoiding the stem base.
Tie initial growth loosely to its support until it begins to climb naturally.

Watering and feeding

Water regularly during the first two years while the root system establishes, especially in dry spells, as clematis are thirsty plants. Once established, water deeply during prolonged drought. Feed in early spring with a balanced or potassium-rich fertiliser such as a tomato feed to encourage flowering, and mulch annually with well-rotted manure or compost, keeping it away from the crown.

Pruning: understanding the three groups

Correct pruning is the single most important skill for clematis success, and it depends entirely on flowering habit.

Group 1 (early flowering, prune after flowering)

Includes Clematis armandii and montana types, which flower on the previous year's growth. Prune lightly straight after flowering only to remove dead or overcrowded stems and control size; hard pruning removes next year's flowers.

Group 2 (large-flowered hybrids, prune in late winter)

Includes 'Nelly Moser' and 'The President'. In late February, cut back to a strong pair of buds, removing weak or dead growth, retaining a framework of healthy stems for the first flush, with a second flush later on new growth.

Group 3 (late-flowering, prune hard in late winter)

Includes viticella types and 'Etoile Violette', flowering on current year's growth. In late February, cut all stems back hard to a pair of strong buds around 20-30cm above ground level. This is the easiest group for beginners.

Clematis wilt

Clematis wilt is a fungal disease that causes sudden blackening and collapse of stems, particularly in large-flowered hybrids. If wilt strikes, cut affected stems back to healthy growth or ground level and destroy the debris; do not compost it. Deep planting encourages dormant buds below soil level, so the plant can usually regrow even if top growth is lost. Viticella types, such as those in Group 3, show good resistance.

Propagation

Propagate clematis by layering in summer: bend a low, flexible stem to the ground, nick the underside, bury the section and peg it down, leaving the tip exposed. Roots should form within a year, after which the new plant can be severed from the parent. Softwood cuttings taken in early summer are also possible but require more care with humidity.

Growing clematis in pots

Compact varieties suit large containers of at least 45cm diameter with good drainage. Use a loam-based compost such as John Innes No.3, provide a support built into the pot, and shade the container itself with other pots or a decorative sleeve to keep roots cool. Water more frequently than border-grown plants and feed fortnightly through the growing season.

Common problems

Problem	Symptom	Fix
Clematis wilt	Sudden blackening and collapse of stems	Cut back to healthy growth, plant deeply next time
Aphids	Sticky new shoots, distorted leaves	Encourage ladybirds, spray with soapy water if severe
Powdery mildew	White coating on leaves in dry summers	Improve air circulation, water at the base
Slugs and snails	Chewed young shoots	Protect new growth with barriers or torchlight removal

Month-by-month care calendar

Month	Task
January-February	Prune Group 2 and Group 3 varieties
March	Apply mulch and balanced feed
April-May	Tie in new growth, watch for early aphids
June-August	Deadhead, water in dry weather, prune Group 1 after flowering
September	Continue watering, watch for mildew
October-November	Plant new clematis, clear fallen debris
December	Plan next year's pruning group, check supports

How to Grow Clematis: Complete UK Care Guide