Centaurea cyanus
Common Name(s):
- Phonetic Spelling
- sen-TAR-ee-ah sigh-AN-us
- Description
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Often seen growing as a weed in fields and along roads and railroads, Cornflower is a hardy, low maintenance cool season annual with striking blue flowers in the Asteraceae (aster) family. Genus came from the popular name of various plants in the late 14th century, from Medieval Latin centaurea, from Latin centaureum, from Greek kentaureion, from kentauros "centaur", so called because the plant's medicinal properties were discovered by Chiron the centaur. Specific epithet means blue for flower color. Plants reseed and naturalize easily so dead-heading is necessary to control the seeds. However, if the goal is to bring birds and butterflies into the garden, limit the dead-heading. It is an attractive and long-lasting cut flower. Because it does better in cooler climates, seeds should be started indoors 6-8 weeks before last frost, or in mild winter climates can be seeded in situ directly outdoors in the fall.
Cornflower is very adaptable and will tolerate poor soils and no fertilization. It tolerates low water conditions but prefers medium moisture, well-drained soils. Cornflower prefers full sun to light shade but the stems will flop with too much shade. Taller plants may need staking or need to be planted with other plants that will hold them up.
A blue cornflower was featured by Corning Glass Works in their initial oven-to-table ware line. It became the trademark of Corning consumer products for three decades.
Place the plant in a container to better control the seeds or a naturalized area where the plant will reseed itself.
Insects, Diseases, and Other Plant Problems: They have no serious insect or disease problems to note. Wilt, rots and rusts are possible. Also watch for aphids and mealybugs.
- See this plant in the following landscape:
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Attributes:
- Genus:
- Centaurea
- Species:
- cyanus
- Family:
- Asteraceae
- Life Cycle:
- Annual
- Recommended Propagation Strategy:
- Seed
- Country Or Region Of Origin:
- Western Asia, Europe
- Distribution:
- Throughout the US and southern Canada
- Wildlife Value:
- Birds and butterflies use the flowers and fruit as a food source
- Play Value:
- Easy to Grow
- Wildlife Food Source
- Particularly Resistant To (Insects/Diseases/Other Problems):
- Deer and drought tolerant
- Edibility:
- Edible
- Dimensions:
- Height: 1 ft. 0 in. - 3 ft. 0 in.
- Width: 1 ft. 0 in. - 2 ft. 0 in.
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Whole Plant Traits:
- Plant Type:
- Annual
- Edible
- Habit/Form:
- Erect
- Growth Rate:
- Medium
- Maintenance:
- High
- Texture:
- Medium
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Cultural Conditions:
- Light:
- Full sun (6 or more hours of direct sunlight a day)
- Partial Shade (Direct sunlight only part of the day, 2-6 hours)
- Soil Texture:
- Clay
- High Organic Matter
- Loam (Silt)
- Soil pH:
- Acid (<6.0)
- Alkaline (>8.0)
- Neutral (6.0-8.0)
- Soil Drainage:
- Good Drainage
- Moist
- Available Space To Plant:
- Less than 12 inches
- USDA Plant Hardiness Zone:
- 2a, 2b, 3a, 3b, 4a, 4b, 5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b, 9a, 9b, 10a, 10b, 11a, 11b
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Fruit:
- Fruit Color:
- Cream/Tan
- Display/Harvest Time:
- Fall
- Fruit Type:
- Achene
- Fruit Length:
- < 1 inch
- Fruit Width:
- < 1 inch
- Fruit Description:
- Finely hairy, straw-colored at maturity with a tuft of short, stiff, light brown bristles at the tip.
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Flowers:
- Flower Color:
- Blue
- Pink
- White
- Flower Inflorescence:
- Cyme
- Head
- Flower Value To Gardener:
- Edible
- Good Cut
- Showy
- Flower Bloom Time:
- Summer
- Flower Shape:
- Wheel
- Flower Petals:
- 7 - 20 petals/rays
- Bracts
- Flower Size:
- 1-3 inches
- Flower Description:
- An intense blue color arranged in heads approximately 1.5 inches in diameter, with a ring of a few large, spreading ray florets surrounding a central cluster of disc florets
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Leaves:
- Leaf Color:
- Gray/Silver
- Green
- Leaf Feel:
- Smooth
- Leaf Type:
- Simple
- Leaf Arrangement:
- Alternate
- Leaf Shape:
- Lanceolate
- Pinnatifid
- Leaf Margin:
- Lobed
- Hairs Present:
- Yes
- Leaf Length:
- 1-3 inches
- Leaf Width:
- < 1 inch
- Leaf Description:
- Leaves are alternate, 1 to 4 inches long, pointed at the tip that are sparsely to moderately covered in long, matted hairs, a distinguishing characteristic of this plant.
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Stem:
- Stem Color:
- Gray/Silver
- Green
- Stem Is Aromatic:
- No
- Stem Form:
- Straight
- Stem Surface:
- Hairy (pubescent)
- Stem Description:
- Single stems from the base of the plant that then branch, are sparsely to moderately covered in woolly hairs; initially erect but tend to flop over without support of surrounding vegetation or stakes.
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Landscape:
- Landscape Location:
- Container
- Meadow
- Naturalized Area
- Landscape Theme:
- Cottage Garden
- Cutting Garden
- Edible Garden
- Design Feature:
- Border
- Attracts:
- Butterflies
- Pollinators
- Songbirds
- Resistance To Challenges:
- Deer
- Problems:
- Weedy