Question From: MICHIGAN
Q: lost the war on treating my Black-eyed Susans last summer with Black Spots and intense treatment with fungicide. We dug them up and threw them all away. this year do I treat soil with something before planting again? live in Rochester Hills, Michigan.
The disease is Septoria, leaf spot or both. It's almost impossible to eliminate. Spraying the soil and leaves as soon as they begin to emerge with regular applications of allowed copper fungicide may help. Overhead watering is a no no and spacing to improve circulation will also help. You'll probably lose the battle however . Consider growing the tall native black-eyed Susan which is resistant. Best And Happy Yardening, Nancy