Why has my clematis suddenly wilted and died back?

Clematis wilt is a fungal disease that blocks the water-conducting tissue in a stem. It affects large-flowered hybrids most, and it is far less serious than it looks — the plant survives if it can reshoot from below soil level.

Step by step

1. Confirm it is wilt.A stem, or the whole plant above a point, collapses suddenly with the leaves still green. There is often a dark discoloured or shrunken patch at the base of the affected stem.
2. Rule out drought.Drought wilting affects the whole plant evenly and recovers after watering. Wilt is abrupt, often confined to one or two stems, and does not recover.
3. Rule out slug or physical damage.Clematis stems are brittle and a stem snapped by wind, a strimmer or a slug ring-barking it at the base produces identical sudden wilting. Check the stem base carefully.
4. Cut the affected stem to ground level.All the way down, below the point of damage. Remove and bin the material rather than composting it.
5. Water and wait.A plant that was planted deeply usually reshoots from dormant buds below ground within a few weeks. Keep it watered and mulched while it does.
6. Plant deeply in the first place.New clematis should go in with the crown about 75 to 100mm below soil level. This is the single thing that determines whether a plant survives wilt.
7. Keep the roots cool and moist.A slab, a low-growing plant, or a thick mulch over the root area. Clematis want their heads in sun and their roots shaded.
8. Improve airflow.Congested growth against a wall stays damp and encourages infection. Train stems out and thin crowded growth.
9. Choose viticella types if it keeps happening.Viticella, alpina, montana and macropetala clematis are far more resistant to wilt than the large-flowered hybrids, which are the main victims.
10. Feed and mulch in spring.A strong plant recovers from wilt far better. Clematis are hungry and appreciate a spring feed and an annual mulch.

Tips

• Plant clematis 75 to 100mm deeper than the pot. It is what lets a plant survive wilt.
• Cut the affected stem right to the ground and bin it — half measures leave the infection in place.
• Viticella clematis rarely get wilt at all.

Common mistakes

• Planting a clematis at the same depth as it was in the pot — There are then no dormant buds below soil level, so a plant that gets wilt has nothing to reshoot from and is often lost outright.
• Cutting the wilted stem back only to the visible damage — The fungus is usually further down the stem than the collapse suggests. Cut to ground level and remove the material entirely.

If it doesn't work

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