Flower profile

Wavyleaf thistle

Cirsium undulatum

Native in the lower 48

Wavyleaf thistle is a wildflower that USDA PLANTS lists as native in the lower 48 states. It's on our flower lists for 3 states, and across the U.S. it's most often seen in bloom in May–July.

26states

3of our state lists

4,639U.S. sightings*

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

On our lists for: Kansas, North Dakota, Oklahoma

Quick look

Cirsium undulatum is a species of thistle known by the common names wavyleaf thistle and gray thistle. It is native to much of central and western North America from British Columbia east to Manitoba and south as far as the State of Durango in Mexico. It has also been found outside of its native range as an introduced species.
From Wikipedia's article Cirsium undulatum, 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 native in the lower 48 states and records it in 26 states. ^{USDA PLANTS}
NatureServe lists it as native to Oklahoma, Kansas and North Dakota. ^NatureServe
In Oklahoma, most iNaturalist sightings of it in flower come in May–July. ^iNaturalist
In Kansas, most iNaturalist sightings of it in flower come in June–July. ^iNaturalist
iNaturalist has 493 research-grade sightings of it in Oklahoma, ranking #67 among the 110 flowers on our Oklahoma list. ^iNaturalist
iNaturalist has 434 research-grade sightings of it in Kansas, ranking #57 among the 109 flowers on our Kansas list. ^iNaturalist
iNaturalist has 81 research-grade sightings of it in North Dakota, ranking #79 among the 109 flowers on our North Dakota list. ^iNaturalist

Wavyleaf thistle gift ideas

Handmade wavyleaf thistle gifts from independent makers.

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When does it bloom?

Flowering records by month across the U.S. (iNaturalist research-grade observations marked “Flowering”) (376 records)

Bloom time in each of our 3 states

State	Type	Peak bloom	Sightings*
Oklahoma	Native	May–July	493
Kansas	Native	June–July	434
North Dakota	Native	few records	81

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
Oklahoma: No list Oklahoma has no state law listing endangered or threatened plants, so we show NatureServe's Oklahoma ranks instead. NatureServe: SNR, not yet ranked in Oklahoma.
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: S5, secure in Kansas.
North Dakota: No list North Dakota has no state law listing endangered or threatened plants, so we show NatureServe's North Dakota ranks instead. NatureServe: SNR, not yet ranked in North Dakota.
Rare elsewhere: Other states where NatureServe ranks it rare or missing: IA (S1), MO (S1), NV (S2). (S1 critically imperiled, S2 imperiled, SH possibly extirpated, SX presumed extirpated.)

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 wavyleaf thistle in 26 states.

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recorded by USDA PLANTS on our state lists not recorded

See the full list of states

Arizona, California, Colorado, Georgia, Idaho, Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Missouri, Montana, Nebraska, Nevada, New Mexico, North Dakota, Oklahoma, Oregon, Pennsylvania, South Dakota, Texas, Utah, Washington, Wisconsin, Wyoming.

Oklahoma counties with USDA records: Beaver, Beckham, Bryan, Canadian, Carter, Cimarron, Cleveland, Comanche, Creek, Custer, Grady, Kingfisher, Lincoln, Logan, Love, Marshall, McClain, Murray, Oklahoma, Payne, Pottawatomie, Roger Mills, Rogers, Tillman, Tulsa, Washita, Woods, Woodward.

Kansas counties with USDA records: Allen, Anderson, Atchison, Barber, Barton, Bourbon, Brown, Butler, Chase, Chautauqua, Cherokee, Cheyenne, Clark, Clay, Cloud, Coffey, Comanche, Cowley, Crawford, Decatur, Dickinson, Doniphan, Douglas, Edwards, Elk, Ellis, Ellsworth, Finney, Ford, Franklin, Geary, Gove, Graham, Grant, Gray, Greeley, Greenwood, Hamilton, Harper, Harvey, Haskell, Hodgeman, Jackson, Jefferson, Jewell, Johnson, Kearny, Kingman, Kiowa, Labette, Lane, Leavenworth, Lincoln, Linn, Logan, Lyon, Marion, Marshall, McPherson, Meade, Miami, Mitchell, Morris, Morton, Nemaha, Neosho, Ness, Norton, Osage, Osborne, Ottawa, Pawnee, Phillips, Pottawatomie, Pratt, Rawlins, Reno, Republic, Rice, Riley, Rooks, Rush, Russell, Saline, Scott, Sedgwick, Seward, Shawnee, Sheridan, Sherman, Smith, Stafford, Stanton, Stevens, Sumner, Thomas, Trego, Wabaunsee, Wallace, Washington, Wichita, Wilson, Woodson, Wyandotte.

North Dakota counties with USDA records: Barnes, Billings, Bowman, Burke, Burleigh, Cass, Cavalier, Divide, Dunn, Eddy, Emmons, Golden Valley, Grand Forks, Grant, Hettinger, Kidder, Logan, McKenzie, McLean, Mercer, Morton, Mountrail, Oliver, Pembina, Ransom, Richland, Rolette, Sargent, Sheridan, Slope, Stark, Stutsman, Williams.

More Oklahoma flowers

Common yarrow

Achillea millefolium

Native

🌼 Blooms in OK: April–June

White snakeroot

Ageratina altissima

Native

🌼 Blooms: August–October

Sunflowers

Helianthus

★ KS state flowerNative

🌼 Blooms: June–October

Sources

USDA, NRCS. PLANTS Database, profile CIUN.
iNaturalist, Cirsium undulatum: taxonomy, research-grade observation counts and “Flowering” annotations, retrieved October 17, 2026.
Wikipedia, Cirsium undulatum (lead quoted under CC BY-SA 4.0).
Oklahoma: Oklahoma Noxious Weed Law (2 O.S. § 3-220).
Kansas: Kansas noxious weeds (K.A.R. 4-8-44, as amended 2026).
North Dakota: North Dakota state noxious weeds (N.D. Admin. Code 7-06-01-02), as listed by the ND Department of Agriculture.
USFWS, ECOS species database (ESA listing check), October 17, 2026.
NatureServe Explorer, Cirsium undulatum (global and state ranks).
Edibility and toxicity: no source found (marked "not well documented").
Photo: brybrysciguy via iNaturalist · CC BY 4.0 · resized.