What is wrong with my clematis plant?
The bottom leaves of my clematis are turning yellow and have powdery substance on it. How can I save it?
Certified GKH Gardening Expert
I'm afraid that this is a little more sinister than powdery mildew. Downy mildew can be a little more detrimental to the health of the plant.
This article will help you to get rid of this: https://www.gardeningknowhow.com/plant-problems/disease/downy-mildew.htm