What Is The Awful Brown “disease” Or” Rot” That Afflicts Brown-eyed Susans’ Leaves And How To STOP It?

Question

All brown-eyed susans and many echinaceas seem to have this problem. What is the solution?

Answer 1

These articles should help:

https://www.gardeningknowhow.com/ornamental/flowers/black-eyed-susan/rudbeckia-leaf-spot.htm

https://extension.psu.edu/echinacea-diseases

https://extension.umd.edu/resource/aster-yellows-disease-flowers/