black spots on my rudbekia (black eyed susan) leaves

Question

I have a large flower bed with lots of black eyed susans. This year one particular section became covered with black spots which I now know are likely a fungus. Other Black eyed Susan plants at the other end of the garden do not have these spots. My question is if I transplant some of the plants that do have these spots on the leaves to another flower bed will they come back next summer with the same spots and if so can it spread to my healthy ones that dont have the spots. I woould really appreciate your advice. Thank you. Sandy

Answer 1

Transplanting infected plants will transplant the fungus or virus as well. There are several diseases of black-eyed susans that cause blackening leaves, both fungal and bacterial. One is devastating to the plant, others are more of a cosmetic issue. It is safer to divide a healthy plant this fall (or move one of the numerous seedlings if you let a healthy plant go to seed) than transplanting a diseased plant. Here is a thorough description of Rudbeckia diseases: https://www.extension.umn.edu/garden/yard-garden/flowers/diseases-of-rudbeckia/