Echinacea purpurea, commonly called purple coneflower, is a North American native and it will grow in the British Isles. A hardy perennial, echinacea purpurea grows from seed and root division. Seeds germinate reliably and mature in one year. Add echinacea purpurea to a plant garden, a wild meadow area, a border area or a perennial flower garden. Plants grow 60 cm to 1.5 m (2 to 5 feet) tall and bloom between June and August. Start echinacea purpurea from seed in March or early April.
Mix equal parts potting soil, peat moss and well-rotted compost in a bucket. Add water until the soil mix is evenly damp and crumbly.
Fill seed-starting trays, cell-packs or planting pots with the damp soil mix. Leave 1.2 cm (1/2 inch) between the top of the container and the top of the soil. Smooth out the top without compacting the material.
Place echinacea purpurea seeds on the soil 2.5 cm (1 inch) apart. Take a handful of the soil mix and scatter it over the surface to cover the seeds with 3 mm to 6 mm (1/8 to 1/4 inch) of material.
Place the seed trays in a greenhouse, indoors or on a covered porch where the seeds will get filtered light. Keep the air temperature at 21.1 degrees Celsius (70 degrees Fahrenheit) for best germination results.
Mist the soil daily or every two days to keep the soil environment around the seed damp. Use a spray bottle with a gentle mist setting to avoid disturbing the seeds. Echinacea seeds germinate in one to three weeks.
Transplant echinacea purpurea into individual 4-inch pots when the seedlings grow 5 cm (2 inches) tall and produce at least one set of true leaves. Fill the transplant pots to 1.2 cm (1/2 inch) below the lip of the pot with damp potting soil.
Lift the seedlings out of the seed-starting tray or cell packs. Slide a butter knife under the soil and lift up. Separate the seedlings with your fingertips if the roots have grown together.
Plant one echinacea seedling in each pot with the base of the stem level with the soil line. Keep the seedlings in a greenhouse for the first year and transplant them into the garden the following spring.