Bloomipedia
Musk thistle (Carduus nutans)
Photo: Nicholas Stockmaster via iNaturalist · CC BY 4.0 · resized

Flower profile

Musk thistle

Carduus nutans

Musk thistle (Carduus nutans) is a flowering plant in the Asteraceae family, introduced in the lower 48 states, blooming mostly April–July across the U.S.

Introduced in the lower 48

Musk thistle is a wildflower that USDA PLANTS lists as introduced in the lower 48 states. It's on our flower lists for 12 states, and across the U.S. it's most often seen in bloom in April–July.

45states where USDA records it
12Bloomipedia state lists include it
27,654U.S. sightings*

*iNaturalist research-grade observations, as of October 17, 2026.

On our lists for: Arkansas, Colorado, Iowa, Kansas, Missouri, Montana, Nebraska, New Mexico, Oklahoma, South Dakota, Utah, Wyoming

🚫
Regulated invasive plant in Colorado, Wyoming, Missouri, Utah, New Mexico, Oklahoma, Kansas and Nebraska. It's on those states' official invasive plant lists (Colorado: List B noxious weed; Wyoming: State designated noxious weed; Missouri: Noxious weed (sale prohibited); Utah: Class 3 noxious weed (containment); New Mexico: Class C noxious weed; Oklahoma: Noxious weed (landowners must control it); Kansas: Category C noxious weed; Nebraska: Noxious weed (landowners must control it)). Please don't plant or share it there. 8 CCR 1206-2 WY designated noxious weeds 2 CSR 70-45.005 R68-9-3 NMDA noxious weed list 2 O.S. § 3-220 K.A.R. 4-8-44 25 NAC 10-001.02

Quick look

Carduus nutans is a biennial plant in the daisy and sunflower family Asteraceae with the common names musk thistle, nodding thistle, and nodding plumeless thistle. It is native to regions of Europe, Central Asia, and North Africa, where it is a scattered pasture plant. The musk thistle has been declared as invasive in North America, Australia, New Zealand, and South Africa.

  • 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 introduced in the lower 48 states and records it in 45 states. USDA PLANTS
  • In Colorado, most iNaturalist sightings of it in flower come in June–September. iNaturalist
  • In Wyoming, most iNaturalist sightings of it in flower come in July–September. iNaturalist
  • iNaturalist has 4,477 research-grade sightings of it in Colorado, ranking #25 among the 160 flowers on our Colorado list. iNaturalist
  • iNaturalist has 1,221 research-grade sightings of it in Wyoming, ranking #11 among the 113 flowers on our Wyoming list. iNaturalist
  • iNaturalist has 958 research-grade sightings of it in Missouri, ranking #67 among the 177 flowers on our Missouri list. iNaturalist

When does it bloom?

Flowering records by month across the U.S. (iNaturalist research-grade observations marked “Flowering”) (2,307 records)
Bloom time in the 12 states whose Bloomipedia list includes it
StateTypePeak bloomSightings*
ColoradoIntroducedJune–September4,477
WyomingIntroducedJuly–September1,221
MissouriIntroducedfew records (47)958
UtahIntroducedJuly–September853
MontanaIntroducedfew records (45)829
New MexicoIntroducedfew records (29)711
OklahomaIntroducedMay–June606
ArkansasIntroducedMay–June598
KansasIntroducedfew records (16)461
South DakotaIntroducedfew records (19)366
NebraskaIntroducedfew records (11)363
IowaIntroducedfew records (9)296

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
State rare plant lists
Not listed Not on the official rare plant list in 4 of our 12 states.
See each state
Missouri
Not listed Not on Missouri Wildlife Code endangered species (3 CSR 10-4.111), plants. NatureServe: SNA, not applicable (usually because it isn't native there) in Missouri. 3 CSR 10-4.111
New Mexico
Not listed Not on New Mexico state endangered plant species (19.21.2.9 NMAC). NatureServe: SNA, not applicable (usually because it isn't native there) in New Mexico. 19.21.2.9 NMAC
Nebraska
Not listed Not on Nebraska threatened and endangered species (163 Neb. Admin. Code ch. 4, § 004). NatureServe: SNA, not applicable (usually because it isn't native there) in Nebraska. 163 NAC 4-004
Iowa
Not listed Not on Iowa endangered, threatened and special concern plants (Iowa Admin. Code r. 571-77.3). NatureServe: SNA, not applicable (usually because it isn't native there) in Iowa. IAC 571-77.3
Colorado
No list Colorado has no state law listing endangered or threatened plants, so we show NatureServe's Colorado ranks instead. NatureServe: SNA, not applicable (usually because it isn't native there) in Colorado.
Wyoming
No list Wyoming has no state law listing endangered or threatened plants, so we show NatureServe's Wyoming ranks instead. NatureServe: SNA, not applicable (usually because it isn't native there) in Wyoming.
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.
Montana
No list Montana has no state law listing endangered or threatened plants, so we show NatureServe's Montana ranks instead. NatureServe: SNA, not applicable (usually because it isn't native there) in Montana.
Oklahoma
No list Oklahoma has no state law listing endangered or threatened plants, so we show NatureServe's Oklahoma ranks instead. NatureServe: SNA, not applicable (usually because it isn't native there) in Oklahoma.
Arkansas
No list Arkansas has no state law listing endangered or threatened plants, so we show NatureServe's Arkansas ranks instead. NatureServe: SNA, not applicable (usually because it isn't native there) in Arkansas.
Kansas
No list Kansas's endangered and threatened list (K.A.R. 115-15-1) covers animals only, so we show NatureServe's Kansas ranks for plants. NatureServe: SNA, not applicable (usually because it isn't native there) in Kansas.
South Dakota
No list South Dakota's endangered and threatened list (ARSD 41:10:02) covers animals only, so we show NatureServe's South Dakota ranks for plants. NatureServe: SNA, not applicable (usually because it isn't native there) in South Dakota.
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?

For peopleNot well documented

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.

For petsNot well documented

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 musk thistle in 45 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, Georgia, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, 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, Virginia, Washington, West Virginia, Wisconsin, Wyoming; District of Columbia.

Colorado counties with USDA records: Boulder, El Paso, Garfield, Grand, Jefferson, La Plata, Larimer, Logan, Mesa, Montezuma, Montrose, Rio Blanco, San Miguel, Teller.

Wyoming counties with USDA records: Albany, Big Horn, Campbell, Carbon, Converse, Crook, Fremont, Goshen, Hot Springs, Johnson, Laramie, Lincoln, Natrona, Niobrara, Park, Platte, Sheridan, Sublette, Sweetwater, Teton, Uinta, Washakie, Weston.

Missouri counties with USDA records: Cass, Jackson, Marion, St. Louis, Webster.

Names, range and relatives

Native status by region (USDA PLANTS): Canada: Introduced; Lower 48 states: Introduced.

Other scientific names (synonyms in USDA PLANTS): Carduus macrocephalus, Carduus macrolepis.

County records: USDA PLANTS lists it in 632 counties across 42 states; the most are in Kansas (60), Virginia (51), Nebraska (41).

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 Colorado flowers

Rubber rabbitbrush (Ericameria nauseosa)

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🌼 Blooms in CO: August–October
Common yarrow (Achillea millefolium)

Common yarrow

Achillea millefolium

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🌼 Blooms in CO: June–September
Dotted gayfeather (Liatris punctata)

Dotted gayfeather

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🌼 Blooms in CO: July–September

Sources