Helianthus giganteus (giant sunflower or tall sunflower), is a species of Helianthus native to the eastern United States and eastern and central Canada, from Newfoundland west to Alberta south to Minnesota, Mississippi, and South Carolina. Helianthus giganteus is a perennial herbaceous plant growing up to 4 m (over 13 feet) tall. The leaves are slender, lanceolate. The flower heads are bright yellow, up to 7 cm (2.8 inches) in diameter. They are most commonly found in valleys with wet meadows or swamps.