Nine species of Echinacea coneflowers are native to the United States, but purple coneflower, or Echinacea purpurea, is the only variety that is widely cultivated. Several different Echinacea cultivars are commercially available.
Coneflowers are perennial herbaceous plants with long, narrow leaves and prominent orange or yellowish-brown cones in the center, surrounded by narrow, elongated daisy-like petals. The petals are usually purple or reddish-purple, but they occasionally appear in yellow or white. They range in height between 14 and 45 inches with a 12- to 38-inch spread.
Coneflowers, which are hardy in U.S. Department of Agriculture Plant Hardiness Map zones 3 through 9, grow in prairies, open woodlands and thickets across the United States. Their native range extends from Ohio and Iowa as far south as Georgia and Louisiana. They prefer full sunlight and well-drained sand, clay or limestone soil. Echinacea plants are drought-tolerant, but have a tendency to become aggressive.
Coneflower plants are susceptible to attack by Japanese beetles. Echinacea is susceptible to bacterial infections such as Xanthomonas and Pseudomonas leaf spot. They are also prone to Botrytis blight, aster yellows and powdery mildew.