Flower profile
Elk thistle
Cirsium scariosum
Elk thistle (Cirsium scariosum) is a flowering plant in the Asteraceae family, native in the lower 48 states, blooming mostly May–August across the U.S.
Elk thistle is a wildflower that USDA PLANTS lists as native in the lower 48 states.
*iNaturalist research-grade observations, as of October 17, 2026.
On our lists for: Wyoming
Quick look
Cirsium scariosum is a species of thistle known by the common names meadow thistle, elk thistle and dwarf thistle. It is native to much of western North America from Alberta and British Columbia, south to Baja California. There are also isolated populations on the Canadian Atlantic Coast, on the Mingan Archipelago in Québec, where it is called the Mingan thistle.
- It belongs to the Asteraceae family. iNaturalist
- USDA PLANTS describes it as an herb (forb) with a biennial, perennial life cycle. USDA PLANTS
- USDA PLANTS lists it as native in the lower 48 states and records it in 11 states. USDA PLANTS
- NatureServe lists it as native to Wyoming. NatureServe
- iNaturalist has 675 research-grade sightings of it in Wyoming, ranking #33 among the 113 flowers on our Wyoming 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
- G5 Secure worldwide. NatureServe
- Wyoming
- No list Wyoming has no state law listing endangered or threatened plants, so we show NatureServe's Wyoming ranks instead. NatureServe: S4, apparently secure in Wyoming.
- 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 elk thistle in 11 states.
recorded by USDA PLANTS on our state lists not recorded
See the full list of states
Arizona, California, Colorado, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, Washington, Wyoming.
Wyoming counties with USDA records: Albany, Carbon, Fremont, Hot Springs, Johnson, Lincoln, Natrona, Park, Sublette, Sweetwater, Teton, Washakie.
Names, range and relatives
Native status by region (USDA PLANTS): Canada: Native; Lower 48 states: Native.
Other scientific names (synonyms in USDA PLANTS): Carduus americanus, Carduus coloradensis, Cirsium acaulescens, Cirsium americanum, Cirsium butleri, Cirsium coloradense, Cirsium congdonii, Cirsium ×erosum, Cirsium erosum, Cirsium kelseyi, Cirsium lacerum, Cirsium magnificum and 4 more.
County records: USDA PLANTS lists it in 135 counties across 9 states; the most are in Idaho (29), California (24), Utah (24).
Other Cirsium on Bloomipedia (12): Bull thistle, Creeping thistle, Bristle thistle, Cobwebby thistle, Field thistle, Texas thistle, Wavyleaf thistle, Tall thistle, New Mexico thistle, Pitcher's thistle.
More from the Asteraceae family (212 on Bloomipedia; most observed first): Common yarrow, Goldenrods, White snakeroot, Sunflowers, Chicory, Black-eyed Susan, Common dandelion, Firewheel.
More Wyoming flowers
Sources
- USDA, NRCS. PLANTS Database, profile CISC2.
- iNaturalist, Cirsium scariosum: taxonomy, research-grade observation counts and “Flowering” annotations, retrieved October 17, 2026.
- Wikipedia, Cirsium scariosum (lead quoted under CC BY-SA 4.0).
- Wyoming: Wyoming state designated noxious weeds (W.S. 11-5-102(a)(xi)), as listed by the Wyoming Weed & Pest Council.
- USFWS, ECOS species database (ESA listing check), October 17, 2026.
- NatureServe Explorer, Cirsium scariosum (global and state ranks).
- Edibility and toxicity: no source found (marked "not well documented").
- Photo: Arvel Hernandez via iNaturalist · CC BY 4.0 · resized.