Coneflowers (echinacea) have either pink, red, purple or white flowers with an orange center cone. The flowers do best when receiving full sun. The plants do encounter some problems such as root rot, mildew, wilt and Japanese beetles.
Coneflowers do need to be watered, but they do not do well in soil that is constantly wet. When the roots of the plant are constantly wet, this causes root rot. Many times this is not due to overwatering, but to water from winter rain and melting snow.
When the leaves of the coneflower have a white powdery covering on them, the plant has mildew. A 1,000-square-foot sample of soil contains 30 pounds of fungi. Most of these fungi are beneficial to the plant, but a few—such as that which causes mildew—can be harmful. Preventative cultural controls against the fungi can be made to ensure healthy plant growth.
Holes in the flowers and leaves of the coneflower can be detrimental to the plant and are most often caused by Japanese beetles. Japanese beetles can cause extreme damage to plants, especially roses.