Q.Perennial Garden Leaf Issues
I have several plants – Oakleaf hydrangea, black-eyed Susans, and coneflower – where the leaves have holes in them and may also have rust disease. The plants are growing, but they do not look very healthy. I am unable to find any information on treatment. I have tried water and soap, but it does not appear to help. I have not tried soap, oil and water, which was my next option. Removing the damaged leaves would leave the plant almost bare.
Certified GKH Gardening Expert
This article should help with that: https://www.gardeningknowhow.com/plant-problems/disease/learn-about-plant-rust-disease-and-rust-treatment.htm