Powdery mildew is a fungal disease that many landscape plants are prone to contracting. Remove the affected plant parts, rake and remove fallen leaves, and try pruning to open the plant up to better air circulation. If you can keep moisture off the leaves of the plant by applying water directly to the soil, you'll reduce the humidity around the plant and remove one of the causes of fungal growth. There are garden fungicides that will protect the uninfected leaves of your clematis, but prevention of fungal diseases is easier than stopping the disease in progress! |