Black-Eyed Susan Concern
At the end of the season last summer here in St. Paul, Minnesota, I noticed a large quantity of black powder at the base of my 4 ft x 3 ft patch of blacked-eyed Susan plants. It looked as though black 'coal dust' had been laced throughout the patch, from the ground and up about 8 inches. Any ideas what would cause this and how would I keep it from happening again? They are planted in the middle of a 20 x 10 foot garden, receive a lot of sun, are planted in black dirt, and the garden has cedar chips sprinkled on top of the dirt.
Certified GKH Gardening Expert
That is called sooty mold. This article will help you in case it comes back: