Helianthus grosseserratus, commonly known as sawtooth sunflower or thick-tooth sunflower, is a perennial sunflower in the family Asteraceae, with a large flowering head (inflorescence). The plant may reach 3–12 feet (91–366 cm) in height and is found along streams, damp prairies and roadsides in the eastern and central parts of Canada and the United States, primarily in the northern Great Plains and Great Lakes Region, with additional populations as far as Maine, Georgia, and Texas. It prefers full sun and moist, fertile loamy soil with high organic content.