Flower profile

Musk thistle

Carduus nutans

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–August.

45states

12of our state lists

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.
From Wikipedia's article Carduus nutans, CC BY-SA 4.0.

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–October. ^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 110 flowers on our Colorado list. ^iNaturalist
iNaturalist has 1,221 research-grade sightings of it in Wyoming, ranking #11 among the 107 flowers on our Wyoming list. ^iNaturalist
iNaturalist has 958 research-grade sightings of it in Missouri, ranking #67 among the 109 flowers on our Missouri 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.

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State flower print
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Birth-flower necklace
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Wildflower seed favors
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Botanical tea towel
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Pressed-flower frame
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Flower-garden mug
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When does it bloom?

Flowering records by month across the U.S. (iNaturalist research-grade observations marked “Flowering”) (2,307 records)

Bloom time in each of our 12 states

State	Type	Peak bloom	Sightings*
Colorado	Introduced	June–October	4,477
Wyoming	Introduced	July–September	1,221
Missouri	Introduced	May–July	958
Utah	Introduced	June–September	853
Montana	Introduced	June–September	829
New Mexico	Introduced	June–October	711
Oklahoma	Introduced	April–June	606
Arkansas	Introduced	May–July	598
Kansas	Introduced	few records	461
South Dakota	Introduced	few records	366
Nebraska	Introduced	few records	363
Iowa	Introduced	few records	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
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.
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}
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.
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}
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.
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}
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.

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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.

More Colorado flowers

Common yarrow

Achillea millefolium

Native

🌼 Blooms in CO: June–September

White snakeroot

Ageratina altissima

Native

🌼 Blooms: August–October

Sunflowers

Helianthus

★ KS state flowerNative

🌼 Blooms: June–October

Sources

USDA, NRCS. PLANTS Database, profile CANU4.
iNaturalist, Carduus nutans: taxonomy, research-grade observation counts and “Flowering” annotations, retrieved October 17, 2026.
Wikipedia, Carduus nutans (lead quoted under CC BY-SA 4.0).
Colorado: Colorado noxious weed lists A, B and C (8 CCR 1206-2, eff. May 15, 2025).
Wyoming: Wyoming state designated noxious weeds (W.S. 11-5-102(a)(xi)), as listed by the Wyoming Weed & Pest Council.
Missouri: Missouri Wildlife Code endangered species (3 CSR 10-4.111), plants.
Missouri: Missouri noxious weed list (2 CSR 70-45.005).
Utah: Utah noxious weed list (Utah Admin. Code R68-9-3).
Montana: Montana noxious weed list (Admin. R. Mont. 4.5.206–4.5.210).
New Mexico: New Mexico state endangered plant species (19.21.2.9 NMAC).
New Mexico: New Mexico Noxious Weed List (NM Department of Agriculture, updated June 2020).
Oklahoma: Oklahoma Noxious Weed Law (2 O.S. § 3-220).
Arkansas: Arkansas State Plant Board noxious weeds and prohibited plants (2 CAR § 50-101).
Kansas: Kansas noxious weeds (K.A.R. 4-8-44, as amended 2026).
South Dakota: South Dakota statewide noxious weeds (ARSD 12:62:03:01.06).
Nebraska: Nebraska threatened and endangered species (163 Neb. Admin. Code ch. 4, § 004).
Nebraska: Nebraska noxious weeds (25 Neb. Admin. Code ch. 10, § 001.02).
Iowa: Iowa endangered, threatened and special concern plants (Iowa Admin. Code r. 571-77.3).
Iowa: Iowa noxious weeds (Iowa Code § 317.1A).
USFWS, ECOS species database (ESA listing check), October 17, 2026.
NatureServe Explorer, Carduus nutans (global and state ranks).
Edibility and toxicity: no source found (marked "not well documented").
Photo: Nicholas Stockmaster via iNaturalist · CC BY 4.0 · resized.