|Scientific Name||Centaurea cyanus|
|Common Names||English: Cornflower; German: Kornblume; French: Bleuet des champs; Spanish: Aciano, Azulejo|
|Description||Annual in summer crops, hibernating to biennial in winter crops, 20-70 cm (7.87 - 27.55 inch) tall.|
Young plant with rosettes, shiny blue flowers.
Dense, vigorous, broad-oval to oval, narrowing to the base.
Up to 1 m (39.37 inch) tall, tomentose to arachnoid pubescent, herbaceous, loosely wooly-hairy when young but losing this as they mature.
Leaves narrow, often linear, mostly entire, or the lower ones sometimes shallowly toothed or lobed, up to 13 cm (5.12 inch) long and 1 cm (0.39 inch) wide, excluding the lobes, white-woolly on the lower surface.
Flower heads bowl-shaped, solitary at the ends of the branches, 1-2 cm (0.39 - 0.78 inch) tall.
Phyllaries ovoid to lanceolate, with fine vertical lines, the edges papery and fringed, lacking spines.
The flowers are an intense blue color, produced in flowerheads (capitula), 1.5 - 3 cm (0.59 - 1.18 inch) diameter, with a ring of a few large, spreading ray florets surrounding a central cluster of disc florets.
Summer - autumn.
2 - 4 mm (0.078 - 0.157 inch) long. Achene 3 - 4 mm (0.12 - 0.16 inch), yellowish-brown to blackish, 3.5 - 4 mm (0.14 - 0.16 inch) long, tipped by orange-brown pappus of bristles.
Silky-cottony seeds, whitely at the end, otherwise blue-gray with white stripes. Germination in autumn and spring.
Viability of Seeds
5 - 10 years.
Germination depth up to 3 cm (1.18 inch).
700 - 1,600 seeds/plant.
Meadows, pastures, waysides, parks.
Loose, nutrient-rich loam and sandy soils.
Additional Crop Information
Cereals, especially winter cereals and oil seed rape, sparsley in potatoes or sugar beets.
C. cyanus causes high yield reduction due to a strong competition for light but usually does not interfere with combine harvesting.
Useful non-chemical contribution to Integrated Weed Management
Careful seed cleaning and monitoring of seed propagators.
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