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Centaurea cyanus
Also called Garden Cornflower, Bachelor's Button, Bluebonnets, Blaver, Blue Bottle, Blue Poppy, Bluebottle
Cornflower is an annual wildflower from Europe with branched grey-green stems and bright blue, daisy-like flowers that bloom all summer. It grows easily from seed in full sun and is best sown directly where it is to flower.
Centaurea cyanus, commonly known as cornflower or bachelor's button (among other names), is an annual flowering plant in the family Asteraceae native to Europe. In the past, it often grew as a weed in cornfields (in the broad sense of "corn", referring to grains, such as wheat, barley, rye, or oats), hence its name.
C. cyanus is now endangered in its native habitat by agricultural intensification, particularly by over-use of herbicides. However, it is now also naturalized in many other parts of the world, including North America and parts of Australia.
Several cultivars of Centaurea cyanus with varying pastel colours, including pink and purple, have been selected for ornamental purposes. The species is also grown for the cut flower industry in Canada for use by florists. Doubled blue cultivars (such as 'Blue Boy' or 'Blue Diadem') are most commonly used for this purpose, but white, pink, lavender and black (actually a very dark maroon) cultivars are also used, albeit to a lesser extent.
Centaurea cyanus is native to temperate Europe, but is widely naturalized in many other parts of the world, including North America and parts of Australia through introduction as an ornamental plant in gardens and as a seed contaminant in crop seeds.
Centaurea behen · Dusty miller · Fiordaliso di Capraia · Maltese star-thistle · Perennial Cornflower · Common Knapweed · Yellow star-thistle · Spotted knapweed · Centaurea tchihatcheffii
Text excerpted from the Wikipedia article Centaurea cyanus by its contributors, under CC BY-SA 4.0; the excerpts and the care summary drawn from them are shared under the same licence.
The care summary was written by AI (Claude, Anthropic) from the sources on this page, with general growing knowledge where they are silent. Check before relying on it.
Life form, climate and native range: World Checklist of Vascular Plants, Royal Botanic Gardens, Kew (CC BY 3.0), reformatted; see Plants of the World Online.
Pet safety from the ASPCA toxic and non-toxic plant lists.
