Flower profile
Cotton thistle
Onopordum acanthium
Cotton thistle is a wildflower that USDA PLANTS lists as introduced in the lower 48 states. In Utah it's most often seen in bloom in June–October.
*iNaturalist research-grade observations, as of October 17, 2026.
On our lists for: Utah
Quick look
Onopordum acanthium is a flowering plant in the family Asteraceae. It is native to Europe and Western Asia from the Iberian Peninsula east to Kazakhstan, and north to central Scandinavia, and widely naturalised elsewhere, with especially large populations present in the United States and Australia. It is a vigorous biennial plant with coarse, spiny leaves and conspicuous spiny-winged stems.
- It belongs to the Asteraceae family. iNaturalist
- USDA PLANTS describes it as an herb (forb) with a biennial life cycle. USDA PLANTS
- USDA PLANTS lists it as introduced in the lower 48 states and records it in 37 states. USDA PLANTS
- NatureServe lists it as not native to Utah. NatureServe
- In Utah, most iNaturalist sightings of it in flower come in June–October. iNaturalist
- iNaturalist has 960 research-grade sightings of it in Utah, ranking #58 among the 109 flowers on our Utah list. iNaturalist
State flower gift ideas
This one is a regulated invasive plant, so here are state flower gifts instead.
🌱 Sample spot. Handmade gift picks from independent shops will appear here once our shop partnership is approved. These cards are placeholders, not real products.
-
Placeholder
State flower print
-
Placeholder
Birth-flower necklace
-
Placeholder
Wildflower seed favors
-
Placeholder
Botanical tea towel
-
Placeholder
Pressed-flower frame
-
Placeholder
Flower-garden mug
When does it bloom?
In Utah, most flowering sightings come in June–October.
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
- Utah
- No list Utah has no state law listing endangered or threatened plants, so we show NatureServe's Utah ranks instead. NatureServe: SNA, not applicable (usually because it isn't native there) in Utah.
- 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?
None of the sources we checked (NC State Extension (no page for this plant), USDA PLANTS) say whether it's edible or poisonous for people.
It isn't on the ASPCA plant list.
🌿 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 cotton thistle in 37 states plus Washington, D.C.
recorded by USDA PLANTS on our state lists not recorded
See the full list of states
Alabama, Arizona, California, Colorado, Connecticut, Delaware, Florida, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Maryland, Massachusetts, Michigan, Minnesota, Missouri, Montana, Nebraska, Nevada, New Jersey, New Mexico, New York, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, Texas, Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin, Wyoming; District of Columbia.
Utah counties with USDA records: Beaver, Cache, Millard, Salt Lake, Summit, Tooele, Uintah, Utah, Wasatch, Washington, Weber.
More Utah flowers
Sources
- USDA, NRCS. PLANTS Database, profile ONAC.
- iNaturalist, Onopordum acanthium: taxonomy, research-grade observation counts and “Flowering” annotations, retrieved October 17, 2026.
- Wikipedia, Onopordum acanthium (lead quoted under CC BY-SA 4.0).
- Utah: Utah noxious weed list (Utah Admin. Code R68-9-3).
- USFWS, ECOS species database (ESA listing check), October 17, 2026.
- NatureServe Explorer, Onopordum acanthium (global and state ranks).
- Edibility and toxicity: no source found (marked "not well documented").
- Photo: Daughter Dad via iNaturalist · CC BY 4.0 · resized.