Coreopsis tripteris aka Tall Coreopsis

Coreopsis tripteris is a tall perennial in the daisy family. Gardeners also call it tall tickseed or golden crown. NC State lists the same species as Anacis tripteris. Its native range spans eastern Canada and central and eastern America. It grows in prairies, woodland edges, and lowland forests. It also occurs in places where rivers scour the ground.

This plant forms upright clumps and spreads through rhizomes. It usually reaches 4–8 feet (1.2–2.4 metres) tall. RHS gives an upper garden height of 8.2 feet (2.5 metres). Some plants reach 10 feet (3 metres), according to NC State. RHS lists a spread of 4.9–8.2 feet (1.5–2.5 metres). Smooth, hollow stems may branch in their upper half. They range from green to a dull blue-green. Paired green leaves have smooth edges and no hairs. Lower leaves split into three to five narrow parts. Upper leaves lack stalks and remain whole. RHS describes the leaves as scented and deciduous.

Yellow flower heads rise on upright stems from midsummer into autumn. Missouri Botanical Garden gives July through September as the bloom season. Chicago Botanic Garden records flowers into October. Each head spans about 1.5–2 inches (3.8–5 centimetres). Yellow rays ring a dark brown to maroon central disc. The flowers have a faint scent like anise. Small, flat achenes ripen from August through October. These dark brown or black fruits have pale winged edges. Flowers draw pollinators, including butterflies, while birds eat the seeds.

Full sun suits this plant, though RHS also allows partial shade. It grows in many soils when water drains well. It tolerates clay, rocky ground, poor soil, heat, and drought. Dry soil produces shorter, thinner plants. Rich, moist soil produces taller, fuller growth that may sprawl. Sources list USDA zones 3–8 and UK hardiness H5. Its height suits the rear of a flower border. It also fits meadows, prairie plantings, and wildflower gardens. The blooms work as cut flowers, and deer tend to avoid it.

Care needs are low, but seedlings can spread strongly. Removing faded heads helps limit new plants. Tall stems may need support, especially in windy sites. Poor drainage can cause crown rot; slugs and snails may attack. Otherwise, sources report few serious pest or disease problems. Cut dead stems to ground level at year’s end. NC State marks it safe for cats, dogs, and horses. The supplied evidence gives no human food use.