Leaf Spot on Rudbeckia
Once thought to be the answer to low maintenance perennial gardens, Goldsturm Rudbeckia’s reputation has been tarnished by several leaf spot diseases.
A bacterial and several fungal leaf spot diseases cause purplish-black spots on the leaves of rudbeckia. Severe infestation can totally blacken the leaves and cause the plants to dieback a bit earlier in fall. Fortunately most of the diseases are cosmetic and the plants will continue to flower and return each year.
Reduce the risk of this disease by providing adequate light and air circulation around the plants. Use a soaker hose or watering wand to apply water directly to the soil when needed.
In fall, remove and destroy all diseased plant parts.
If disease is a yearly problem, plant more resistant cultivars like Becky, Cherokee Sunset, Irish eyes, or Prairie Sun.
A bit more information: Or keep the plants and hide the diseased leaves. Plant something slightly shorter in front of the Goldsturm Rudbeckia plants to mask the discolored leaves, but allow the flowers to show through.