Autumn clematis is a perennial flowering vine subject to few life-threatening pests. Grow in full to partial sun with well-drained, rich soil and keep the roots cool with mulch to ensure autumn clematis is strong enough to withstand its few pests.
Disease pests include stem rot or wilt (Ascochyta clematidina), which causes vine dieback, and powdery mildew (order Erysiphales), which dusts the leaves in fungi. Aphids flock to autumn clematis, followed by ladybugs, which feed on the aphids and on the pollen. Clematis borer may also cause stem dieback, while slugs, earwigs and birds cause only cosmetic damage to flowers. Root knot nematodes cause several problems for autumn clematis.
Insect pests prevail during the warmest months. Nematodes feed actively once the soil warms. Birds eat the overwintering buds if they spot them. Stem rot is active in summer, causing wilt and dieback just before the autumn blooms open. Powdery mildew thrives where air circulation is low.
Douse clematis in insecticidal soap to control aphids. Fence out rabbits or distract them with a trap crop. Plant clematis in soil that’s high in organic matter, and add organic mulch to feed the fungi that prey on nematodes. Grow in a well-ventilated area to avoid powdery mildew.