Michelle Grabowksi, UMN Extension Educator
By September, plants may not have a single green leaf remaining. Septoria rudbeckiae will survive in plant debris, so it is best to remove infected stems and leaves at the end of the season. These should be discarded in a backyard compost that gets hot or at a municipal composting site. Next year, thin plants and remove volunteer seedlings to provide good air movement around plants. Water with drip irrigation or early in the day so leaves dry quickly in the sun. Look for leaf spots early in the season and pinch off infected leaves. Never remove more than 1/3rd of a plants foliage. For more information read Diseases of Rudbeckia.