Flower profile

Tall thistle

Cirsium altissimum

Tall thistle (Cirsium altissimum) is a flowering plant in the Asteraceae family, native in the lower 48 states, blooming mostly August–September across the U.S.

Native in the lower 48

Tall thistle is a wildflower that USDA PLANTS lists as native in the lower 48 states. It's on our flower lists for 4 states, and across the U.S. it's most often seen in bloom in August–September.

33states where USDA records it

4Bloomipedia state lists include it

3,546U.S. sightings*

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

On our lists for: Arkansas, Kansas, Nebraska, Oklahoma

Quick look

Cirsium altissimum is a North American species of plants in the tribe Cardueae within the family Asteraceae. Common names are tall thistle or roadside thistle. The species is native to the eastern and Central United States.
From Wikipedia's article Cirsium altissimum, CC BY-SA 4.0.

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 native in the lower 48 states and records it in 33 states. ^{USDA PLANTS}
NatureServe lists it as native to Arkansas, Oklahoma, Kansas and Nebraska. ^NatureServe
iNaturalist has 626 research-grade sightings of it in Arkansas, ranking #84 among the 170 flowers on our Arkansas list. ^iNaturalist
iNaturalist has 612 research-grade sightings of it in Oklahoma, ranking #52 among the 159 flowers on our Oklahoma list. ^iNaturalist
iNaturalist has 600 research-grade sightings of it in Kansas, ranking #38 among the 151 flowers on our Kansas list. ^iNaturalist

When does it bloom?

Flowering records by month across the U.S. (iNaturalist research-grade observations marked “Flowering”) (184 records)

Bloom time in the 4 states whose Bloomipedia list includes it

State	Type	Peak bloom	Sightings*
Arkansas	Native	few records (26)	626
Oklahoma	Native	few records (18)	612
Kansas	Native	few records (7)	600
Nebraska	Native	few records (16)	218

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
Arkansas: No list Arkansas has no state law listing endangered or threatened plants, so we show NatureServe's Arkansas ranks instead. NatureServe: SNR, not yet ranked in Arkansas.
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.
Nebraska: Not listed Not on Nebraska threatened and endangered species (163 Neb. Admin. Code ch. 4, § 004). NatureServe: SNR, not yet ranked in Nebraska. ^{163 NAC 4-004}
Rare elsewhere: Other states where NatureServe ranks it rare or missing: DC (SX), DE (SH), NJ (SX), NY (SX), VA (S1). (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 edibility or poison notes on its page), USDA PLANTS) say whether it's edible or poisonous for people. ^{NC State Extension}

For petsNot well documented

It isn't on the ASPCA plant list, and NC State Extension doesn't flag it for pets.

🌿 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 tall thistle in 33 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, Arkansas, Connecticut, Delaware, Florida, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Nebraska, New Jersey, New York, North Carolina, North Dakota, Ohio, Oklahoma, Pennsylvania, South Carolina, South Dakota, Tennessee, Texas, Virginia, West Virginia, Wisconsin; District of Columbia.

Arkansas counties with USDA records: Arkansas, Benton, Boone, Carroll, Clark, Cleburne, Cross, Drew, Faulkner, Franklin, Garland, Hot Spring, Howard, Independence, Jefferson, Johnson, Lawrence, Logan, Madison, Marion, Monroe, Montgomery, Nevada, Newton, Perry, Phillips, Polk, Pope, Pulaski, Sebastian, Stone, Washington, Yell.

Oklahoma counties with USDA records: Adair, Alfalfa, Cleveland, Creek, Delaware, Kay, Latimer, Le Flore, McCurtain, McIntosh, Murray, Muskogee, Noble, Oklahoma, Okmulgee, Ottawa, Payne, Pontotoc, Pottawatomie, Tulsa.

Kansas counties with USDA records: Allen, Anderson, Atchison, Barton, Bourbon, Brown, Butler, Chase, Chautauqua, Cherokee, Clay, Cloud, Coffey, Cowley, Crawford, Dickinson, Doniphan, Douglas, Elk, Ellsworth, Franklin, Geary, Greenwood, Harper, Harvey, Jackson, Jefferson, Jewell, Johnson, Kingman, Kiowa, Labette, Leavenworth, Lincoln, Linn, Lyon, Marion, Marshall, McPherson, Miami, Montgomery, Morris, Nemaha, Neosho, Osage, Ottawa, Phillips, Pottawatomie, Reno, Republic, Rice, Riley, Rooks, Saline, Sedgwick, Shawnee, Sheridan, Smith, Sumner, Wabaunsee, Washington, Wilson, Woodson, Wyandotte.

Names, range and relatives

Other scientific names (synonyms in USDA PLANTS): Carduus altissimus.

County records: USDA PLANTS lists it in 708 counties across 31 states; the most are in Missouri (86), Illinois (76), Kansas (64).

Other Cirsium on Bloomipedia (12): Bull thistle, Creeping thistle, Bristle thistle, Cobwebby thistle, Field thistle, Texas thistle, Wavyleaf thistle, Elk 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 Arkansas flowers

Black-eyed Susan

Rudbeckia hirta

★ MD state flowerNative

🌼 Blooms in AR: May–July

Late boneset

Eupatorium serotinum

Native

🌼 Blooms in AR: August–October

Bitterweed

Helenium amarum

Native

🌼 Blooms in AR: June–October

Sources

USDA, NRCS. PLANTS Database, profile CIAL2.
iNaturalist, Cirsium altissimum: taxonomy, research-grade observation counts and “Flowering” annotations, retrieved October 17, 2026.
Wikipedia, Cirsium altissimum (lead quoted under CC BY-SA 4.0).
Arkansas: Arkansas State Plant Board noxious weeds and prohibited plants (2 CAR § 50-101).
Oklahoma: Oklahoma Noxious Weed Law (2 O.S. § 3-220).
Kansas: Kansas noxious weeds (K.A.R. 4-8-44, as amended 2026).
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).
USFWS, ECOS species database (ESA listing check), October 17, 2026.
NatureServe Explorer, Cirsium altissimum (global and state ranks).
Edibility and toxicity: NC State Extension.
Photo: Ken Clark via iNaturalist · CC BY 4.0 · resized.