Purple coneflower

Identification and origin

Echinacea purpurea belongs to the family Asteraceae, the daisy family. It is native to the central and eastern United States, from Texas and Oklahoma to the Great Lakes and North Carolina, where it grows in prairies, savannas, and along woodland edges. The genus name comes from the Greek echinos, “hedgehog,” for the prickly center of the flower; the epithet purpurea refers to its purple color.

It is an upright herbaceous perennial that forms a clump 2–4 ft tall and 12 in – 2 ft wide. Its stiff, hairy stems need no staking. The basal leaves, lance-shaped to oval, rough to the touch and toothed, reach 6 in long; they become smaller and narrower toward the top of the stems.

The solitary flower heads, up to 5 in across, pair a domed, purplish-brown disk of spiny florets with pinkish-purple ray petals that often droop. Bloom begins in midsummer and continues in flushes until frost. The fruits are small dark achenes, a favorite of goldfinches. The flowers feed bees and butterflies, and the dry, hollow stems serve as nests for native bees. Its foliage also feeds the caterpillars of the silvery checkerspot butterfly, Chlosyne nycteis. Native American peoples used the root to treat many ailments.

Common cultivars include ‘Magnus’, with large deep-pink flowers that do not droop; ‘Ruby Star’ (‘Rubinstern’), crimson-rose; ‘White Swan’ and ‘Alba’, with white flowers; ‘Kim’s Knee High’, a compact plant 12–18 in tall; and ‘Merlot’, with burgundy stems. The orange, yellow, or red coneflowers sold at garden centers are often hybrids with other species, sometimes less durable in poorly drained soil.

Light

It blooms best in full sun, with at least six hours of direct light a day. It tolerates part shade with a few hours of direct sun, but it produces the most flowers in sun. It is not a houseplant: grow it in the garden, in a perennial border, a meadow planting, or a native plant garden.

Watering

It prefers evenly moist but well-drained soil. After planting, until the roots are established, check soil moisture by pushing a finger into it, and water when it begins to dry. Water at the base rather than sprinkling the foliage: leaves that stay wet encourage disease. Once established, it handles drought and heat well. Soil that stays waterlogged, on the other hand, should be avoided: it encourages stem rot, and hybrids are especially vulnerable.

Potting mix

It adapts to almost any soil, whether clay, loam, sand, or rocky ground, with a pH near neutral, as long as it drains. Ideally, give it deep, humus-rich, well-drained soil. It is not a heavy feeder: without a soil test, a slow-release fertilizer applied in early spring, just before new growth starts, is enough.

Temperature

Very hardy, it is grown in USDA zones 3 to 8. It tolerates summer heat and humidity. Winter cold is part of its cycle: its seeds even need a period of moist cold to germinate. In winter the top growth dies back, and the crown resprouts in spring.

Repotting

This is mostly a matter of planting. Fall is the best season to set out new plants. Space them generously so air circulates between clumps, which keeps the foliage dry and limits the spread of disease. Divide clumps every three to four years, in spring or fall, to keep them from becoming crowded.

Pruning

Removing faded flowers as they appear extends the bloom season. At the end of the season, though, leave some flower heads: their seeds feed birds in winter, and the plant will self-sow. Dead leaves and stems can be removed in fall, winter, or early spring, before new growth begins. For bees that nest in the stems, you can cut them back to 12 in – 2 ft and leave those stubs standing until they break down.

Propagation

Seed is the most common method, and the plant readily self-sows. Indoors, sow at 64–70 °F, covering the seeds lightly, and keep the seed bed moist by misting: seedlings emerge in 10 to 20 days and can be transplanted about three to four weeks after sowing. Outdoors, you can sow in spring or summer, up to two months before frost. A seed-grown plant takes two years or more to form a good-sized clump. ‘Magnus’ and ‘White Swan’ come true from seed.

Division, in spring or fall, reproduces a cultivar exactly. Take root cuttings from late fall to early winter. For consistent flower color, cultivars such as ‘Bright Star’ are propagated by division or stem cuttings.

Common problems

• Distorted, greenish flowers, with small flower heads sprouting from the center: aster yellows, a disease spread by a leafhopper and incurable; dig up and destroy the plant.
• Tufts of stunted, twisted flower parts: eriophyid mites living in the buds; cut the plant back to the ground in fall and destroy the debris.
• Leaf spots in late summer, white powdery coating: leaf spot, powdery mildew, or anthracnose, encouraged by crowded planting.
• Plant collapsing at the base: stem rot, often in poorly drained soil.
• Chewed foliage: Japanese beetles, aphids, or rabbits. Against aphids, insecticidal soap applied three times at five- to seven-day intervals works well.

A single symptom can have several causes: look at the whole plant, the soil, and the site before treating. Deer usually leave it alone.

Toxicity

No toxicity reported: purple coneflower does not appear among plants toxic to dogs and cats, and no veterinary or medical reference flags it as dangerous. Its top growth can even be steeped as a tea. As with any plant, eating a large amount can still cause digestive upset in an animal.