Black-Eyed Susan Concern

Question

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.

Answer 1

That is called sooty mold. This article will help you in case it comes back:
https://www.gardeningknowhow.com/plant-problems/disease/how-to-get-rid-of-sooty-mold.htm