When do I prune a clematis?

Depends entirely on the pruning group — and getting it wrong removes all the flowers. Group 1 (montana, alpina, armandii — flowers on previous year's wood): prune AFTER flowering, just removing dead/damaged stems. Group 2 (large-flowered hybrids like Nelly Moser, Niobe, Henryi): light tidy in February, then a second light prune after first flowering. Group 3 (viticellas, late large-flowered hybrids, C. tangutica): cut to 30 cm above ground in February. If you don't know your group: check the cultivar name in a clematis catalogue or RHS database. If buying a new clematis, the label should state the pruning group.

Why did my clematis suddenly die overnight?

Almost certainly clematis wilt (Calophoma clematidina) — a fungal disease that causes stems to suddenly wilt and turn black, often after the first flowering. Three steps. (1) Cut all affected stems back hard to below the wilt point (often to ground level). (2) Keep watering and feeding — the deep-planted crown is usually fine. (3) The plant will usually re-shoot from below the soil within 4–6 weeks (which is why deep planting matters so much). For chronic wilt problems: replace susceptible Group 2 hybrids with disease-resistant Group 3 viticellas.

Why is my clematis not flowering?

Five common causes. (1) Wrong pruning — cutting at the wrong time removes flowering wood. Identify the group. (2) Too young — most clematis take 2–3 years to settle and flower properly. (3) Hot dry roots — shade the root zone, mulch, water deeply. (4) Not enough sun on the top — needs 4–6 hours direct sun for flowering. (5) Wrong feed — high nitrogen produces leaves not flowers; switch to tomato food for blooms.

What's the best clematis variety for the UK?

For a first or only clematis, pick a Group 3 viticella: easy pruning (cut to 30 cm in February), disease-resistant, prolific from June to September. Etoile Violette (deep violet, vigorous), Madame Julia Correvon (wine red), Polish Spirit (deep purple, AGM), Princess Diana (texensis, tulip-shaped pink). For a big spring climber: Montana var. rubens (pink) or Montana Elizabeth (pale pink, scented). Large-flowered hybrids are striking but prone to wilt; pick named cultivars carefully.

Why do I need to plant a clematis so deep?

Wilt protection. Clematis wilt is the most common UK clematis disease, attacking stems just above the crown. If the clematis is planted at pot depth, all the stems are vulnerable and the whole plant can die. Plant 7–10 cm deeper so the crown sits below soil level — new shoots can then emerge from below ground if upper stems are wilted, saving the plant. This single planting trick prevents 90% of clematis losses in UK gardens. Apply to every clematis you plant.

Can I grow clematis in a pot?

Yes — Group 3 viticellas are best. A 45 cm pot of peat-free compost mixed with garden compost and slow-release fertiliser. Plant 7–10 cm deeper than the pot the clematis came in (same deep-planting rule applies). Water consistently — pot clematis dry out fast and are quick to flop. Feed with tomato food fortnightly during flowering. Repot or top-dress every 2 years. Avoid vigorous montanas (too big) and large-flowered hybrids prone to wilt — viticellas are the pot-friendly group.

Clematis

Plant clematis in spring or autumn, with the crown 7–10 cm BELOW the soil surface (deeper than the pot) — this is the single most important planting rule, and it protects against the devastating clematis wilt disease that kills shallowly-planted plants. The pruning group matters enormously: Group 1 (flowers on old wood — montana, alpina) needs almost no pruning; Group 2 (flowers on old AND new wood — most large-flowered hybrids) gets a light tidy in February; Group 3 (flowers on new wood — viticella, late large-flowered, C. tangutica) gets cut back hard to 30 cm in February. Mismatch the pruning group and you'll cut off all the flowers. Plant in a sunny position with roots in shade, head in sun — a paving slab or low planting at the base shades the roots. Most clematis are hardy (RHS H5–H6).

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