A giant of a wildflower, sawtooth sunflower reaches 10 feet high and sometimes occurs in dense colonies of clumping, branching stems. It has long, coarsely toothed, lance-shaped, arching leaves. The lower half of the plant stem is hairless, smooth, often with a white-waxy coating.
Sawtooth sunflower is a giant perennial herb, usually branched, sometimes occurring in dense colonies of clumping stems. The lower stems are typically hairless and smooth, reddish, sometimes with a white-waxy (glaucous) coating.
The flowerheads are all yellow, to 3½ inches across, with 10–25 fairly wide ray florets. The green involucral bracts beneath the flowerhead are narrowly lanceolate to almost linear, tapering to a long, narrow tip.
Blooms July–October.
The leaves are sessile (stalkless) or with very short stalks, which often have small wings where they attach to the stem. The leaves are lance-shaped, coarsely toothed, and reach about 10 inches long and 2½ inches wide; they fold a bit, lengthwise, along the midvein, and they typically arch downward; the upper leaves are closely spaced, usually alternate.
Key characters:
- Leaves mostly alternate, narrow, folded slightly lengthwise along the midvein, curving downward, margins saw-toothed
- Disk florets yellow
- Involucral bracts narrow, long-tapering, pointed, spreading
- Lower half of the plant stem hairless, smooth, often glaucous.
Similar species: Sunflower species readily hybridize with each other, which can make identification difficult. Not counting hybrids, there are 16 species of Helianthus recorded for Missouri.
For an overview of Missouri’s sunflowers, visit their group page.
Height: 2–10 feet.
Scattered in the northern and western halves of the state; absent from most of the southeastern quarter of Missouri.
Habitat and Conservation
Occurs in bottomland and upland prairies, bases of bluffs, banks of streams and rivers, fens, and margins of ponds and lakes; also ditches, margins of cultivated fields, pastures, railroads, roadsides, and open, disturbed areas.
Status
Native Missouri wildflower.
Human Connections
For Native Americans, sunflowers had a variety of traditional medicinal and other uses. They remain culturally significant through spirituality and through folklore and art.
Many Americans value sunflowers simply for the great beauty they give to roadsides, fencerows, and fields in late summer. It's a grand finale of bright yellow flowers before the purples, oranges, and reds of autumn steal the show.
The species name, grosseserratus, is a mouthful, and it means "coarsely serrated" (coarsely toothed). It refers to the sawtoothed leaf margins. Pronounce it as GRO-sus-suh-RAH-tuss.
Ecosystem Connections
Sunflowers provide nectar and pollen to a great variety of insects. At the same time, they provide a productive hunting ground for spiders, assassin bugs, robber flies, and other predators of the many insects attracted to the flowers.
When the flowers are spent, birds and mammals, including finches and rodents, relish the sunflower seeds. The seeds of sawtooth sunflower look remarkably like the black oil sunflower seeds people use as bird food (those are from a cultivated variety of the common sunflower, Helianthus annuus).
One reason why sunflowers grow so tall is that, in nature, they compete with the eight-foot-tall grasses of our tallgrass prairies. They must raise their heads high in order to attract pollinators.
