Clematis (Clematis spp.) is a large family of flowering vines. The deciduous or evergreen plants come in a variety of sizes and bloom in different colors. Clematis foliage is susceptible to numerous problems.
Clematis plants are prone to clematis wilt caused by Phoma clematidina. The fungal disease leads to wilting and blackening foliage and flowers. The fungus infects the plant roots and moves upward, disrupting the flow of nutrients and water. There are no fungicides to control the disease. Remove severely infected plants entirely.
Mildew fungi leads to a white, powdery growth on clematis foliage and stems. In severe infection, flowers are distorted and foliage wilts. This is accompanied by defoliation. Well-irrigated and mulched plants are less susceptible to the disease. Plants growing in poorly ventilated areas are more prone to mildew. Apply triforine or buprimate as chemical control options.
Small fly (Phytomyza vitalba) infestation causes small blotches on leaf margins. The fly larvae feeding creates tunnels on foliage uppersides. The tunnels are not visible on the undersides. Remove infested leaves and destroy. Insecticidal control options include spraying plants with pirimiphos-methyl or permethrin.