Flower profile
Cornflower
Centaurea cyanus
Cornflower (Centaurea cyanus) is a flowering plant in the Asteraceae family, introduced in the lower 48 states, blooming mostly May–July across the U.S.
Cornflower is a wildflower that USDA PLANTS lists as introduced in the lower 48 states.
*iNaturalist research-grade observations, as of October 17, 2026.
On our lists for: Idaho
Quick look
Centaurea cyanus, commonly known as cornflower or bachelor's button, is an annual flowering plant in the family Asteraceae native to Europe. In the past, it often grew as a weed in cornfields, hence its name.
- It belongs to the Asteraceae family. iNaturalist
- USDA PLANTS describes it as an herb (forb) with a annual life cycle. USDA PLANTS
- USDA PLANTS lists it as introduced in the lower 48 states and records it in 49 states. USDA PLANTS
- NatureServe lists it as not native to Idaho. NatureServe
- iNaturalist has 509 research-grade sightings of it in Idaho, ranking #64 among the 143 flowers on our Idaho list. iNaturalist
When does it bloom?
Conservation status
- Federal (U.S. ESA)
- Not listed No U.S. Endangered Species Act listing in the USFWS ECOS database. USFWS ECOS
- NatureServe global
- GNR Not yet ranked worldwide. NatureServe
- Idaho
- No list Idaho has no state law listing endangered or threatened plants, so we show NatureServe's Idaho ranks instead. NatureServe: SNA, not applicable (usually because it isn't native there) in Idaho.
- Rare elsewhere
- No other U.S. state ranks it S1, S2, SH or SX.
Checked October 17, 2026. Rankings and lists can change, so follow the links for the latest.
Can you eat it?
NC State Extension notes: “Flowers are edible.” NC State Extension
ASPCA's entry “Bachelors Buttons” (Centaurea cyanus) lists it as non-toxic to dogs, cats and horses. Eating lots of any plant can still upset a pet's stomach. ASPCA
🌿 Never eat a wild plant unless you're certain of its ID; this isn't medical advice. Worried about a person? Call Poison Control at 1-800-222-1222. Worried about a pet? Call your vet.
Where does it grow?
USDA PLANTS records cornflower in 49 states plus Washington, D.C.
recorded by USDA PLANTS on our state lists not recorded
See the full list of states
Alabama, Arizona, Arkansas, California, Colorado, Connecticut, Delaware, Florida, Georgia, Hawaii, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin, Wyoming; District of Columbia.
Idaho counties with USDA records: Ada, Bonner, Gem, Idaho, Kootenai, Latah, Lewis, Nez Perce, Washington.
Names, range and relatives
Native status by region (USDA PLANTS): Canada: Introduced; Greenland: Introduced; Hawaii: Introduced; Lower 48 states: Introduced.
Other scientific names (synonyms in USDA PLANTS): Leucacantha cyanus.
County records: USDA PLANTS lists it in 533 counties across 45 states; the most are in Virginia (57), North Carolina (50), Arkansas (25).
Other Centaurea on Bloomipedia (1): Spotted knapweed.
More from the Asteraceae family (212 on Bloomipedia; most observed first): Common yarrow, Goldenrods, White snakeroot, Sunflowers, Chicory, Black-eyed Susan, Bull thistle, Common dandelion.
More Idaho flowers
Sources
- USDA, NRCS. PLANTS Database, profile CECY2.
- iNaturalist, Centaurea cyanus: taxonomy, research-grade observation counts and “Flowering” annotations, retrieved October 17, 2026.
- Wikipedia, Centaurea cyanus (lead quoted under CC BY-SA 4.0).
- Idaho: Idaho noxious weeds (IDAPA 02.06.09, Section 220).
- USFWS, ECOS species database (ESA listing check), October 17, 2026.
- NatureServe Explorer, Centaurea cyanus (global and state ranks).
- Edibility and toxicity: NC State Extension; ASPCA.
- Photo: Samuele Papeschi via iNaturalist · CC BY 4.0 · resized.