Clematis Wilt
Calophoma clematidina
A fungal disease of clematis, mostly the large-flowered hybrids, that causes shoots to wilt and collapse suddenly, often just as the plant is about to flower. The wilt can be alarming because a healthy-looking vine blackens and dies back to the ground in a few days, though the roots usually survive and resprout.
🔎 How to spot it
The first signs are dark spots on the leaves and leaf stalks, which turn black, followed by sudden wilting of one or more stems from the tip down; the leaves droop, blacken, and shrivel. Splitting an affected stem near the base often shows internal blackening or a small dark canker at the point of collapse. The wilt typically strikes the large-flowered hybrids, frequently around budding and bloom.
🥀 Damage it causes
The disease kills shoots and can wilt much or all of the top growth, often destroying the flush of buds and flowers and setting the plant back severely for the season. Young plants in their first year or two are the most vulnerable. The damage looks fatal, but because the fungus usually cannot invade the woody base and roots, the plant commonly regrows from buds at or below ground level.
🔬 What causes it
Clematis wilt is caused by the fungus Calophoma clematidina, whose spores are splashed or carried onto the leaves and young, soft stems, where they germinate in moist conditions and infect, then move down to wilt the stem. The large-flowered hybrids are very susceptible, while the small-flowered species clematis are much more resistant, and old, hardened woody stems resist infection far better than soft new growth.
🛡️ Prevent it
Choose more resistant small-flowered or species clematis where wilt is a recurring problem, and plant clematis deep, with the crown a few inches below the surface, so there are buried buds that can resprout if the top collapses. Keep the base of the plant cool and the foliage able to dry, water at the root rather than over the leaves, and remove and destroy fallen infected leaves and debris where the fungus survives.
🧯 If it is already here
There is no chemical cure available to most gardeners, so management is cultural: as soon as a stem wilts, cut it back to healthy tissue or to ground level and destroy the prunings, disinfecting tools afterward. Because the roots usually live, keep watering and feeding the plant and it will often send up new healthy shoots, sometimes within the same season. Deep planting is the key insurance against losing the whole plant.
💡 Good to know
Clematis wilt looks devastating but is rarely fatal, since the crown and roots typically survive and regenerate, which is exactly why deep planting matters. The large-flowered hybrids suffer most, so gardeners tired of repeated wilt often switch to the tougher small-flowered species. Sudden blackening and collapse of soft stems, with internal staining at the base, distinguishes it from drought or pest wilt.
🌱 Plants it affects
2 plants in the library can be affected by this problem
For educational and informational purposes only. Disease management advice is general guidance drawn from university cooperative extension sources; always identify a problem positively and read and follow the label on any product before use, especially around food crops, children, and pets.