Scientific Name: Helianthus annuus

Common Name: common sunflower

Other Common Names: annual sunflower, sunflower, wild sunflower

Synonyms: Helianthus aridus, Helianthus lenticularis

Habit: Wild sunflower can complete its life cycle in as little as 60 days and can get from 8-15 ft tall. These plants tolerate heat and drought, but perish after the first frost. Blooms first appear in early summer and continue into early fall.

Leaves: When young, the seedlings are bright green and the width is double the length. Large, rough-hairy oval to heart shaped leaves; lower leaves opposite and chordate, the upper, smaller and narrower. The stems are sometimes branched, and the hairs on the stem are coarse. Mature leaves can be 3 or 6 inches (8-15 cm) to 1 foot (30 cm) across, usually with rough hairs.

Identifying Characteristics: The flower heads start out facing the east in the morning, and end up facing the west at the end of the day, following the sun.

Flower Seed Head: There will be 1-12 flowers that bloom during the summer to early fall. Large, gold, red-brown and yellow flower heads 3-12 inches across. Most have yellow ray florets and purplish brown disk florets. The ray florets of sunflowers are sterile, and only the disk florets produce seeds.

Seed Fruit: The seed can be seen in the center of the flower very easily. Fruit is a dry, dark casing with white stripes enclosing a white seed; flattish but plump.

Where Found: Prairies and dry, open areas, and is sometimes a weed in cultivated fields and pastures.

  • Life cycle: summer annual

  • Milky sap: Not Present

  • Plant type: Herb

  • Thorns: Not Present

  • Plant family: Asteraceae

  • Leaf arrangement: opposite

  • Leaf shape: oval; round; heart

  • Ochrea: Present

  • Leaf margin: serrated

  • Stem hairs: has hairs

  • Flower color: yellow

  • Growth habit: upright and nonwoody

  • Stem: round or oval

  • Leaf structure: simple

  • Leaf hairs: has hairs

  • Flower symmetry: radial symetery; bilateral symetry; disymetry

  • Flower diameter: larger

  • Root structure: taproot

  • Leaf stalk: shorter than leaf