An annual sunflower, extremely variable in height and appearance, with hairy stems. Flowerheads of wild form are many per plant, large, with brown disks, and frequently with a double set of yellow ray florets. Disk usually a couple inches in diameter, not including the rays. Blooms July–November. Cultivated forms often have only one, often huge, flowerhead per plant. Leaves are large, ovate to broad, with irregular, large teeth, mostly alternate except the uppermost ones. Lower leaves are usually heart-shaped. All leaves are rough and hairy.
Similar species: There are 16 species of Helianthus in Missouri. Common sunflower’s leaves have long petioles, lacking wings, and are rather broad, with the larger leaves ovate to heart-shaped with irregular, large teeth, and are mostly alternate except those at the very top. Also, its disks are reddish brown to dark purple, while several other sunflowers have yellow disks.
Habitat and Conservation
The common sunflower is a tremendously useful plant historically as well as today.
This species is the most important crop plant that is native to the United States. It is cultivated worldwide for sunflower oil, which is made from the seeds.
At one time Missouri was a leading producer of sunflowers.
The plant is a longtime favorite ornamental for gardeners. Sunflowers are a favorite midsummer selection for cut-flower arrangements.
Sunflowers provide food for livestock and wildlife. MDC plants sunflowers in food plots for wildlife in several of its conservation areas.
The common sunflower is beloved worldwide by painters, photographers, poets, and novelists.
Many baseball players snack on sunflower seeds while in their dugout, instead of the chewing tobacco they historically used.
To learn more, read the fascinating (and fun) book “The Sunflower,” by ethnobotanist and enthusiastic sunflower specialist Charles B. Heiser.
Birds and small mammals eat the seeds, which are rich in oil and proteins, as well as the foliage.
Many kinds of insects visit the flowers for nectar and pollen, and other, predatory insects lie in wait for them.
Because they grow readily on open or disturbed ground, sunflowers help bind the soil.
Where to See Species
Columbia Bottom is for those who love wide, open spaces. It's located in a floodplain at the Confluence of the Mississippi and Missouri Rivers, the two largest in North America.