Plant coneflower in a sunny location that has well-drained, fertile soil. Most can thrive on available rainfall once established, and plenty of sun and heat won't bother them. The long-blooming, colorful flowers are at home in sunny borders, herb gardens, cottage gardens, prairie gardens, or wild gardens.
Propagate by seed, or dig and divide the main rootstalk in spring or fall. Root division is an alternative for all species, but it is most successful with E. purpurea. The best time to divide roots is in early autumn or spring. Cut through the crown of the coneflower clump with a sharp spade. Separate two to three young roots and shoots from the main plant every 4 to 5 years.
Grow coneflower plants from seed following a dormancy-breaking period. Seeds germinate best between 70° and 75°F and, for E. purpurea, after dry prechilling (1 to 3 months at 40°F). Sow seeds indoors 6 to 8 weeks before the last frost date in your area; or sow on the surface of a sandy soil mix in an open cold frame in early spring. (See individual species descriptions for exceptions.) Seeds normally germinate within 10 to 20 days. Transplant seedlings outside after all danger of frost has passed. Coneflower self-sows readily but not aggressively.
In short-season regions, coneflowers may need more than one growing season to produce flowers unless seeds are started early indoors.
In northern areas (zones 3, 4, and 5), plants need to develop roots fast. Pinch off flower buds that develop the first year from seed. The plant will divert its energy into root development. In mild-winter areas, coneflower may grow and flower the first year from seeds sown in the garden.
To extend the flowering period of mature plants, cut off faded flower heads. However, toward season's end, you may want to leave some to dry out on the stems: They make attractive forms in winter, and their seeds attract many birds, especially finches.
Both roots and aboveground parts of E. angustifolia and E. purpurea are the sources of most of the modern echinacea remedies, but the dried roots are used in homemade preparations. Powdered roots and tinctures are sold in health-food stores and some supermarkets.
Allow seed-started plants to grow for 3 to 4 years before harvesting roots; divided plants need two years. Dig them in the autumn after flowering is finished, and cut washed and dried roots that are thicker than 1/2-inch into sections to speed drying. Allow the roots to dry in a warm but shaded place. Replant the crown with smaller roots to continue your supply.
Prepare roots in either of these ways: Grind dried root pieces into a powder. Mix 4 tablespoons of powdered root per quart of water; cover and simmer over low heat for 20 minutes, then strain. Drink the solution hot or cool, 1 to 2 cups per day. The tea cannot be stored because it becomes unstable, which is why most herbalists prepare it in an alcohol tincture.
Make a tincture by covering washed, chopped, and dried root with 1 to 2 inches of 100-proof vodka in a clean glass jar that has an enamel cap. Allow it to steep at room temperature for two weeks, shaking the container daily. Proper dosage is an individual matter, and you should consult with a naturopathic physician or qualified herbalist before using any herb. Echinacea tincture is effective in very small amounts. Generally, half to one full eyedropper (30 to 60 drops) a day in water, juice, or tea is about right.