Well, what ever is the cause, it’s not good. The plant is either infested or infected by leafhoppers and/or eriophid mites. The leafhoppers carry a disease in their saliva that causes the plant to fail in a variety of ways. The mite feeds on coneflower. These bugs lay eggs in the grass and hatch to tunnel up the stems of the flowers. You need to discard the plants and keep the lawn trimmed.
Well, what ever is the cause, it’s not good. The plant is either infested or infected by leafhoppers and/or eriophid mites. The leafhoppers carry a disease in their saliva that causes the plant to fail in a variety of ways. The mite feeds on coneflower. These bugs lay eggs in the grass and hatch to tunnel up the stems of the flowers. You need to discard the plants and keep the lawn trimmed.