Q&As/Other Plant Diseases/Powdery mildew on Clematis
Please help. How do I get mould (white) off my Clematis Duchess of Albany? It has lovely pink flowers but the mould looks terrible.
Clematis ‘Duchess of Albany’ is a vigorous climbing vine which has stunning tulip shaped, deep pink flowers. Unfortunately they are very prone to the type of powdery mildew you mention, which disfigures the plant, especially the leaves.
To lessen the impact of the mildew, position the plant in an open situation where airflow will be enhanced, while still ensuring there is still an adequate support structure for the climber. Make sure you weed the area well around your clematis to stop any infected weeds spreading mildew spores to your plant.
Ensure your Clematis is grown in friable (crumbly textured) soil and has adequate compost worked in around the roots of the plant. Although Clematis are not gross feeders, do apply a very light side dressing of Daltons Premium Rose & Flower fertiliser in spring for best results.
At the end of the growing season cut back excessive growth while retaining a strong framework of the plant.
You can treat the powdery mildew with an organic fungicide spray, but it is best applied at the first sign of infection.