Helianthus angustifolius
Helianthus angustifolius is known by the common name Narrowleaf Sunflower or Swamp Sunflower. It is native to the south-central and eastern United States, found in all the coastal states from Texas to Long Island, and inland as far as Missouri. It is typically found in the coastal plain habitat (both the Atlantic and Gulf), particularly in wet areas.
Helianthus angustifolius is often cultivated for its bright, showy yellow flowers. Leaves are long and narrow, up to 15 cm (6 inches) long. It is a perennial herb from 2 feet high to sometimes as much as 5 feet tall. One plant can produce 3-16 flower heads, each with 10-20 ray florets surrounding at least 75 disc florets.
Grow it in full sun and moist but well-drained, moderately fertile, humus-rich soil. Needs ample moisture, but not, despite one of its names, a flooded swamp. It may require support. This tall U.S. native is great for a perennial border, meadow, or butterfly garden. Zones 6-9. Superb pollinator species for late summer and fall.