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Centaurea cyanus - L.

Common Name Cornflower, Garden cornflower, Blue Bottle, Cornflower
Family Asteraceae or Compositae
USDA hardiness Coming soon
Known Hazards None known
Habitats Once a common weed of cornfields, as a result of modern agricultural practices it is now very rare in the wild[9, 13]. Found especially on porous, nutrient-rich soils[268].
Range Most of Europe, including Britain, to the Near East.
Edibility Rating    (2 of 5)
Other Uses    (2 of 5)
Weed Potential Yes
Medicinal Rating    (2 of 5)
Well drained soil Moist Soil Full sun
Centaurea cyanus Cornflower, Garden cornflower, Blue Bottle, Cornflower

Centaurea cyanus Cornflower, Garden cornflower, Blue Bottle, Cornflower


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Bloom Color: Blue, Lavender, Pink, Purple, White. Main Bloom Time: Early summer, Early fall, Late summer, Mid summer. Form: Upright or erect.

Physical Characteristics

 icon of manicon of flower
Centaurea cyanus is a ANNUAL growing to 1 m (3ft 3in) by 0.3 m (1ft) at a fast rate.
It is not frost tender. It is in flower from June to August, and the seeds ripen from August to October. The species is hermaphrodite (has both male and female organs) and is pollinated by Bees, flies, Lepidoptera (Moths & Butterflies). The plant is self-fertile.
It is noted for attracting wildlife.
Suitable for: light (sandy), medium (loamy) and heavy (clay) soils, prefers well-drained soil and can grow in nutritionally poor soil. Suitable pH: acid, neutral and basic (alkaline) soils and can grow in very alkaline soils.
It cannot grow in the shade. It prefers dry or moist soil and can tolerate drought.



 Cultivated Beds;

Edible Uses

Edible Parts: Flowers.
Edible Uses: Colouring.

The young shoots are edible[7]. Flowers - raw or cooked. The fresh florets can be used in salads[238]. They are used as a vegetable or a garnish[183]. An edible blue dye is obtained from the flowers, used for colouring sugar and confections[183].

Medicinal Uses

Plants For A Future can not take any responsibility for any adverse effects from the use of plants. Always seek advice from a professional before using a plant medicinally.

Antifungal;  Antipruritic;  Antirheumatic;  Antitussive;  Astringent;  Diuretic;  Emmenagogue;  Laxative;  
Ophthalmic;  Purgative;  Tonic.

Cornflower has a long history of herbal use, though it is seldom employed nowadays. In France it is still used as a remedy for tired eyes, but opinions differ as to its efficacy[254, 268]. Traditionally it is said to work best on blue eyes, whilst Plantago major (great plantain) was used for brown eyes[268]. The dried flowers are antipruritic, antitussive, astringent, weakly diuretic, emmenagogue, ophthalmic, very mildly purgative, and tonic[4, 7, 9, 21, 201, 240]. An infusion can be used in the treatment of dropsy, constipation, or as a mouthwash for ulcers and bleeding gums[9, 238]. This infusion is also taken as a bitter tonic and stimulant, improving the digestion and possibly supporting the liver as well as improving resistance to infections[254]. A water distilled from the petals was formerly in repute as a remedy for weak eyes[4] and a soothing lotion for conjunctivitis[7, 240]. The seeds are used as a mild laxative for children[7, 254]. A decoction of the leaves is antirheumatic[7, 254]. Antifungal [303].

Other Uses

Dye;  Hair;  Ink;  Pot-pourri.

A blue ink and a dye is obtained from the petals mixed with alum-water[4, 100, 115, 201]. The dye gives a lovely colour to linen, but it is transient[4]. The dried petals are used in pot-pourri in order to add colour[4, 268]. Extracts of the plant are added to hair shampoos and rinses[238]. Grown as an ornamental plant in gardens and as a cutflower in Canada for florists.

Cultivation details

Landscape Uses:Border, Container, Foundation, Massing, Seashore, Specimen. Succeeds in ordinary garden soil[1, 200]. Prefers a well-drained fertile soil and a sunny position[200]. Tolerates dry, low fertility and alkaline soils[200]. Established plants are drought tolerant[201]. A very ornamental plant[1], there are many named varieties[188]. The flowers are often used in dried-flower arrangements because they retain their colour well[7]. A good plant for bees, butterflies and moths[20, 30, 108]. The cornflower is considered to be a good companion, in small quantities, for cereal crops[18, 20], though another report says that its greedy roots deprive the cultivated plants of nutrients and its tough stem dulls the reaper's sickle[4]. Members of this genus are rarely if ever troubled by browsing deer[233]. Special Features: Not North American native, Invasive, Naturalizing, Suitable for cut flowers, Suitable for dried flowers.


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Seed - sow March in the greenhouse. When they are large enough to handle, prick the seedlings out into individual pots and plant them out in May. The seed can also be sown in situ during April, whilst in areas where the winters are not too cold a sowing in situ during September will produce larger and earlier-flowering plants

Other Names

If available other names are mentioned here

Bachelor's button, cornflower, garden cornflower, boutonniere flower, hurtsickle, Bluebottle, or cyani flower,.

Found In

Countries where the plant has been found are listed here if the information is available

Asia, Australia, Britain, Europe, Hawaii, India, Mediterranean*, North America, Pacific, Poland, Tasmania, Turkey, USA, Yugoslavia.

Weed Potential

Right plant wrong place. We are currently updating this section. Please note that a plant may be invasive in one area but may not in your area so it’s worth checking.

This plant can be weedy or invasive.

Conservation Status

IUCN Red List of Threatened Plants Status : This taxon has not yet been assessed. Possibly endangered in its native habitat by agricultural intensification, particularly over-use of herbicides, destroying its habitat.

Related Plants
Latin NameCommon NameEdibility RatingMedicinal Rating
Centaurea acaulis 00
Centaurea calcitrapaCommon Star Thistle, Red star-thistle11
Centaurea chamaerhaponticum 20
Centaurea depressaIranian knapweed20
Centaurea ibericaIberian Star Thistle, Iberian knapweed12
Centaurea jaceaBrown Knapweed11
Centaurea melitensisMaltese Star Thistle01
Centaurea montanaMountain Cornflower, Perennial cornflower, Mountain Bluet02
Centaurea nigraBlack Knapweed, Lesser knapweed12
Centaurea raphanina 10
Centaurea scabiosaGreater Knapweed02
Centaurea solstitialisSt. Barnaby's Thistle, Yellow star-thistle11


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Subject : Centaurea cyanus  
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