Scientific Name: Centaurea cyanus

Common Name: garden cornflower

Other Common Names: bachelor's button, cornflower, garden cornflower

Synonyms: Leucacantha cyanus

Habit: Erect winter annual that grows to 1.2 m tall with a taproot and often a weed in small grains.

Leaves: Leaves are alternate approximately 5 to 15 cm long and 1 cm wide, lance shaped to linear, hairy, and has entire or slightly toothed margins. Due to the leaf appearance, these plants are often confused for a grass.

Identifying Characteristics: An erect winter annual with long white hairs and blue, white, or pink flowers. Plants may reach 3.5 feet in height.This weed is sometimes confused with both Spotted Knapweed (<a href='../../weedimg/580'> Centaurea maculosa</a>) and corn cockle (Agrostemma githago). However, spotted knapweed forms a basal rosette of leaves during the first year of growth and its leaves are much more deeply lobed than those of cornflower. Additionally, the leaves of corn cockle are joined across the stem and the stems of this plant are swollen at the nodes whereas neither of these characteristics occurs with spotted knapweed or cornflower.

Flower Seed Head: Many solitary heads are produced on long flower stalks (peduncles). Flowers are 2.5 to 5 cm wide and 1.5 to 3 cm long.They are pink, purple, white, and sometimes blue in color.

Seed Fruit: The seed is an achene that is about 4 mm long and 2 mm wide, and is gray in the middle and yellow brown on the ends with pubescense on one end.

Where Found: Found throughout the eastern half of the United States and also in the western states from California to Washington.

  • Life cycle: winter annual

  • Milky sap: Not Present

  • Plant type: Herb

  • Thorns: Not Present

  • Plant family: Asteraceae

  • Leaf arrangement: alternate

  • Leaf shape: lance; needle

  • Leaf margin: entire; serrated

  • Ochrea: Not Present

  • Stem hairs: has hairs

  • Flower color: blue; purple; white; pink

  • Growth habit: upright and nonwoody

  • Stem: round or oval

  • Leaf structure: simple

  • Leaf hairs: has hairs

  • Root structure: taproot

  • Flower symmetry: radial symetery

  • Flower diameter: quarter; larger; half dollar

  • Leaf stalk: none