Control. He says, ‘In 1915 a Bulletin was published which dealt with Ascochyta clematidina, as this fatal disease is named. Plants get sick because of fungus, various clematis diseases and pests. Luckily, this disease does not attack the roots. Here is what to do to try to prevent it from happening to your clematis. The disease is thought to also be affected by water-logging, wind and failed grafts. In fact, the symptoms usually start at the end of the branch and work downwards. Many theories have been advanced as to the cause of Clematis Wilt. The plant droops from the top down, foliage turns slimy and black and it happens very quickly - within a matter of a few hours. DISEASES WILT: Clematis are pretty much trouble free, suffering from just one serious problem known as 'Wilt'. Clematis wilt (sometimes it can be called clematis leaf and stem spot) is a devastating fungal disease. Clematis wilt is a disease caused by a fungus that attacks the structures inside clematis stems. Vicki, generally speaking clematis wilt affects a whole stem and does not spread from the bottom of the plant upwards. It makes clematis vines shrivel and may cause death of the plant. Treatment. - Ken Woolfenden, Webperson Many first time clematis growers get discouraged by wilt damaged vines and then just give up on the plant. Does the Clematis Wilt Disease Really Exist? Disease-Resistant Clematis. Know the signs. Jim Fisk, a clematis expert who was instrumental in making them popular in gardens and who has written several books on clematis, is of the opinion that clematis wilt is not a disease, and he is not alone. Though mostly deciduous vines, the Clematis genus includes evergreens and shrubs. New shoots will emerge and some cultivars will bloom again in the same season. Water is unable to move from the roots to the leaves and the whole plant wilts. Plants with clematis wilt disease will suddenly completely collapse overnight - the foliage turns black (not brown) and the veins take on a purple colour. If those are the symptoms then the plant does indeed have clematis wilt. Be sure to disinfect your tools after pruning the infected plants to avoid transmitting the disease to other plants. Simply prune out the affected stems or trim the plant to the ground. Suddenly, with no warning, all the plant, or sometimes just a part of it, collapses and 'dies' - generally just as the plant was about to flower. Ernest Markham in his book Clematis, published by Country Life Ltd., even has a name for the fungus that is supposed to be the cause of the disease. Clematis wilt is a common problem when growing clematis, especially with the fancier hybrids which have less resistance. These Clematis have been recommended by our Members as being good, reliable plants, easy to grow and resistant to the more common pests and diseases. But the term “clematis wilt” is best reserved for the disease. Clematis vines climbing up a fence or trellis create a cascading wall of flowers and foliage, but powdery mildew can turn these attractive plants into a dying mass. Powdery Mildew on a Clematis.