A number of leaf spots are seen on clematis. Pick off infected leaves when seen. No chemical control is listed. Powdery mildew causes a white powdery growth on the leaves. Spray with benomyl or sulfur.
Crown gall attacks the vines near soil level.
The galls are roundish with an irregular rough surface. Destroy infected plants and avoid infested soil. No chemical control is listed. This information is for educational purposes only. References to commercial products or trade names does not imply endorsement by MSU Extension or bias against those not mentioned.