Purple coneflower (Echinacea purpurea) a hardy perennial that grows throughout the United States is known for its medicinal qualities in treating colds and boosting the immune system. Its prickly seedpod resembles a tiny hedgehog, earning it the name of Echinacea (derived from the Greek word echinos for hedgehog). As an ornamental plant, purple coneflower makes a striking contrast with rubeckia or shasta daisies. Its upright stems produce stately blooms with lavender-pink petals that fold backward exposing the dark cone-shaped center. Hardy to zone 4, purple coneflower can be grown successfully in most parts of the U.S.
Select an area that receives full sun to partial shade. Till the soil to a depth of 8 inches or more and remove any rocks or roots. Add a 2 to 3 inch layer of compost and mix in well with the existing soil.
Apply 12-6-6 fertilizer following the recommended application rate. Mix into the soil to prevent damage to seeds and young roots.
Plant purple coneflower in spring when the soil as warmed to 70 to 75 degrees Fahrenheit. Although they will germinate at lower temperatures, warmer soil speeds germination.
Sow seeds to a depth of 1/8 inch and cover with soil. Firm down with your hands. Water to moisten the soil and seeds and keep moist until seeds germinate in 14 to 30 days.
Thin when seedlings are 3 to 4 inches high, spacing 18 to 24 inches apart. Mature purple coneflower may spread to a width of 2 to 3 feet and need room to grow.
Mulch around the base of the plant to prevent weeds and conserve moisture, if you prefer. Otherwise, keep weeds at bay by pulling them by hand.
Allow the soil to dry before watering. Water deeply once a week to promote lush growth. Although Echinacea is drought tolerant and survives well without supplemental watering (in most areas), growth in improved with regular watering.