Flower profile

Bull thistle

Cirsium vulgare

Introduced in the lower 48

Bull thistle is a wildflower that USDA PLANTS lists as introduced in the lower 48 states. It's on our flower lists for 21 states, and across the U.S. it's most often seen in bloom in July–October.

50states

21of our state lists

60,863U.S. sightings*

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

On our lists for: Connecticut, Delaware, Idaho, Illinois, Iowa, Maine, Maryland, Massachusetts, Michigan, Minnesota, New Hampshire, New Jersey, New York, North Dakota, Ohio, Pennsylvania, Rhode Island, South Dakota, Vermont, Washington, Wisconsin

🚫

Regulated invasive plant in Washington, Pennsylvania and Iowa. It's on those states' official invasive plant lists (Washington: Class C noxious weed; Pennsylvania: Class B noxious weed; Iowa: Primary noxious weed). Please don't plant or share it there. ^{WAC 16-750 PA noxious weed list Iowa Code § 317.1A}

Quick look

Cirsium vulgare, commonly known as spear thistle, bull thistle, or common thistle, is a species of the Asteraceae genus Cirsium, native throughout most of Europe, Western Asia, and northwestern Africa. It is also naturalised in North America, Africa, and Australia and is an invasive weed in several regions. It is the national flower of Scotland.
From Wikipedia's article Cirsium vulgare, 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 introduced in the lower 48 states and records it in 50 states. ^{USDA PLANTS}
In New York, most iNaturalist sightings of it in flower come in July–September. ^iNaturalist
In Washington, most iNaturalist sightings of it in flower come in June–September. ^iNaturalist
iNaturalist has 6,055 research-grade sightings of it in New York, ranking #28 among the 109 flowers on our New York list. ^iNaturalist
iNaturalist has 4,147 research-grade sightings of it in Washington, ranking #37 among the 110 flowers on our Washington list. ^iNaturalist
iNaturalist has 3,876 research-grade sightings of it in Massachusetts, ranking #37 among the 110 flowers on our Massachusetts 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”) (4,596 records)

Bloom time in each of our 21 states

State	Type	Peak bloom	Sightings*
New York	Introduced	July–September	6,055
Washington	Introduced	June–September	4,147
Massachusetts	Introduced	July–September	3,876
Pennsylvania	Introduced	June–September	3,286
Wisconsin	Introduced	July–September	2,955
Michigan	Introduced	June–September	2,847
New Jersey	Introduced	July–October	2,840
Illinois	Introduced	July–September	2,158
Ohio	Introduced	July–October	2,110
Minnesota	Introduced	July–October	1,670
Maryland	Introduced	June–September	1,526
Maine	Introduced	July–September	1,015
Vermont	Introduced	July–September	1,012
New Hampshire	Introduced	July–September	651
Connecticut	Introduced	July–September	649
Idaho	Introduced	July–October	475
Rhode Island	Introduced	few records	412
Iowa	Introduced	few records	293
South Dakota	Introduced	June–September	267
Delaware	Introduced	few records	147
North Dakota	Introduced	few records	110

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
New York: Not listed Not on New York protected native plants (6 NYCRR § 193.3). NatureServe: SNA, not applicable (usually because it isn't native there) in New York. ^{6 NYCRR § 193.3}
Washington: No list Washington has no state law listing endangered or threatened plants (the Washington Natural Heritage Program's rare plant list isn't regulatory), so we show NatureServe's Washington ranks instead. NatureServe: SNA, not applicable (usually because it isn't native there) in Washington.
Massachusetts: Not listed Not on Massachusetts Endangered Species Act list (321 CMR 10.90). NatureServe: SNA, not applicable (usually because it isn't native there) in Massachusetts. ^{MESA list}
Pennsylvania: Not listed Not on Pennsylvania classified native plants (17 Pa. Code Ch. 45, Subchapter B, as amended 2023). NatureServe: SNA, not applicable (usually because it isn't native there) in Pennsylvania. ^{17 Pa. Code Ch. 45}
Wisconsin: Not listed Not on Wisconsin endangered and threatened species list (Wis. Admin. Code NR 27.03). NatureServe: SNA, not applicable (usually because it isn't native there) in Wisconsin. ^{NR 27.03}
Michigan: Not listed Not on Michigan endangered and threatened plants (Mich. Admin. Code R 299.1028, eff. March 20, 2023). NatureServe: SNA, not applicable (usually because it isn't native there) in Michigan. ^{R 299.1028}
New Jersey: Not listed Not on New Jersey Endangered Plant Species List (N.J.A.C. 7:5C-5.1). NatureServe: SNA, not applicable (usually because it isn't native there) in New Jersey. ^{N.J.A.C. 7:5C-5.1}
Illinois: Not listed Not on Illinois List of Endangered and Threatened Flora (17 Ill. Adm. Code 1050), per the Endangered Species Protection Board's 2025 checklist. NatureServe: SNA, not applicable (usually because it isn't native there) in Illinois. ^{IL E&T checklist 2025}
Ohio: Not listed Not on Ohio endangered and threatened plants (Ohio Adm. Code 1501:18-1-03, eff. Dec. 26, 2024). NatureServe: SNA, not applicable (usually because it isn't native there) in Ohio. ^{OAC 1501:18-1-03}
Minnesota: Not listed Not on Minnesota endangered, threatened and special concern plants (Minn. R. 6134.0300). NatureServe: SNA, not applicable (usually because it isn't native there) in Minnesota. ^{Minn. R. 6134.0300}
Maryland: Not listed Not on Maryland threatened and endangered plants (COMAR 08.03.08.05, .06 and .08). NatureServe: SNA, not applicable (usually because it isn't native there) in Maryland. ^{COMAR 08.03.08}
Maine: Not listed Not on Maine Rare Plant List (Maine Natural Areas Program, 2021). E and T are Maine's official endangered and threatened plants (12 M.R.S.); SC and PE are tracking categories. NatureServe: SNA, not applicable (usually because it isn't native there) in Maine. ^{Maine rare plant list}
Vermont: Not listed Not on Endangered and Threatened Plants of Vermont (10 V.S.A. chap. 123; list of Feb 10, 2022). NatureServe: SNA, not applicable (usually because it isn't native there) in Vermont. ^{Vermont E&T list}
New Hampshire: Not listed Not on New Hampshire Official Rare Plants List (Ncr 312, eff. Jan 1, 2020). NatureServe: SNA, not applicable (usually because it isn't native there) in New Hampshire. ^{NH Ncr 312}
Connecticut: Not listed Not on Connecticut Endangered, Threatened and Special Concern Plants (RCSA 26-306; 2015 list). NatureServe: SNA, not applicable (usually because it isn't native there) in Connecticut. ^{CT E/T/SC list}
Idaho: No list Idaho has no state law listing endangered or threatened plants, so we show NatureServe's Idaho ranks instead. NatureServe: SNA, not applicable (usually because it isn't native there) in Idaho.
Rhode Island: Not listed Not on Rhode Island Rare Plants 2016 (RI Natural History Survey, from the RI Wildlife Action Plan; informational, Rhode Island has no state plant-protection listing law). NatureServe: SNA, not applicable (usually because it isn't native there) in Rhode Island. ^{RI rare plants 2016}
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}
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.
Delaware: Not listed Not on Rare and Uncommon Plants of Delaware (DNREC, 2024; informational, Delaware has no state plant-protection list). NatureServe: SNA, not applicable (usually because it isn't native there) in Delaware. ^{DE rare plants 2024}
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: SNA, not applicable (usually because it isn't native there) in North 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 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 bull thistle in 50 states plus Washington, D.C.

AKMEVTNHWAIDMTNDMNILWIMINYRIMAORNVWYSDIAINOHPANJCTCAUTCONEMOKYWVVAMDDEAZNMKSARTNNCSCDCOKLAMSALGAHITXFL

recorded by USDA PLANTS on our state lists not recorded

See the full list of states

Alabama, Alaska, Arizona, Arkansas, California, Colorado, Connecticut, Delaware, Florida, Georgia, Hawaii, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, 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, Vermont, Virginia, Washington, West Virginia, Wisconsin, Wyoming; District of Columbia.

New York counties with USDA records: Albany, Allegany, Bronx, Cattaraugus, Cayuga, Chautauqua, Chemung, Columbia, Cortland, Delaware, Erie, Essex, Genesee, Greene, Hamilton, Jefferson, Kings, Lewis, Livingston, Madison, Monroe, Nassau, New York, Niagara, Oneida, Onondaga, Ontario, Orange, Oswego, Otsego, Putnam, Queens, Richmond, Rockland, Saratoga, Schenectady, St. Lawrence, Suffolk, Tompkins, Ulster, Washington, Westchester, Wyoming.

Washington counties with USDA records: Adams, Asotin, Benton, Chelan, Clallam, Clark, Columbia, Cowlitz, Douglas, Ferry, Franklin, Garfield, Grant, Grays Harbor, Island, Jefferson, King, Kittitas, Klickitat, Lewis, Lincoln, Mason, Okanogan, Pacific, Pend Oreille, Pierce, San Juan, Skagit, Skamania, Snohomish, Spokane, Stevens, Thurston, Wahkiakum, Walla Walla, Whatcom, Whitman, Yakima.

Massachusetts counties with USDA records: Barnstable, Berkshire, Bristol, Dukes, Essex, Franklin, Hampden, Hampshire, Middlesex, Nantucket, Norfolk, Plymouth, Suffolk, Worcester.

More New York flowers

Common yarrow

Achillea millefolium

Native

🌼 Blooms in NY: June–September

White snakeroot

Ageratina altissima

Native

🌼 Blooms in NY: August–October

Chicory

Cichorium intybus

Introduced

🌼 Blooms in NY: June–October

Sources

USDA, NRCS. PLANTS Database, profile CIVU.
iNaturalist, Cirsium vulgare: taxonomy, research-grade observation counts and “Flowering” annotations, retrieved October 17, 2026.
Wikipedia, Cirsium vulgare (lead quoted under CC BY-SA 4.0).
New York: New York protected native plants (6 NYCRR § 193.3).
New York: New York prohibited and regulated invasive species (6 NYCRR Part 575).
Washington: Washington State noxious weed list (WAC 16-750-005, -011, -015).
Massachusetts: Massachusetts Endangered Species Act list (321 CMR 10.90).
Massachusetts: Massachusetts Prohibited Plant List (MDAR) (Text from MDAR's 2023 scientific-name PDF (mass.gov blocks automated downloads); 2024-2026 additions listed on the mass.gov page: Alnus glutinosa, Pyrus calleryana, Miscanthus sinensis, Aralia elata, Rhodotypos scandens, Symplocos paniculata.).
Pennsylvania: Pennsylvania classified native plants (17 Pa. Code Ch. 45, Subchapter B, as amended 2023).
Pennsylvania: Pennsylvania Noxious Weed List (3 Pa.C.S. § 1519, PA Dept. of Agriculture) (PDA's page spells garlic mustard “Allaria petiolata”; we match it as Alliaria petiolata).
Wisconsin: Wisconsin endangered and threatened species list (Wis. Admin. Code NR 27.03).
Wisconsin: Wisconsin invasive species rule (Wis. Admin. Code NR 40.04 prohibited, NR 40.05 restricted).
Michigan: Michigan endangered and threatened plants (Mich. Admin. Code R 299.1028, eff. March 20, 2023).
Michigan: Michigan prohibited and restricted species (NREPA Part 413 and the 2026 Invasive Species Order), as listed by Michigan's Invasive Species Program.
New Jersey: New Jersey Endangered Plant Species List (N.J.A.C. 7:5C-5.1).
New Jersey: New Jersey prohibited invasive plant species (Invasive Species Management Act; propagation banned from Jan 1, 2027, sale from Jan 1, 2030).
Illinois: Illinois List of Endangered and Threatened Flora (17 Ill. Adm. Code 1050), per the Endangered Species Protection Board's 2025 checklist.
Illinois: Illinois Official List of Exotic Weeds (17 Ill. Adm. Code 1100.30, Illinois Exotic Weed Act).
Ohio: Ohio endangered and threatened plants (Ohio Adm. Code 1501:18-1-03, eff. Dec. 26, 2024).
Ohio: Ohio invasive plant species (Ohio Adm. Code 901:5-30-01).
Minnesota: Minnesota endangered, threatened and special concern plants (Minn. R. 6134.0300).
Minnesota: Minnesota Noxious Weed List (Minn. Stat. § 18.79; Minnesota Department of Agriculture, updated January 2026).
Maryland: Maryland threatened and endangered plants (COMAR 08.03.08.05, .06 and .08).
Maryland: Maryland Prohibited Invasive Plant List (COMAR 15.06.04.06; MDA, updated July 2026).
Maine: Maine Rare Plant List (Maine Natural Areas Program, 2021). E and T are Maine's official endangered and threatened plants (12 M.R.S.); SC and PE are tracking categories.
Maine: Maine Do Not Sell invasive plant list (01-001 C.M.R. ch. 273).
Vermont: Endangered and Threatened Plants of Vermont (10 V.S.A. chap. 123; list of Feb 10, 2022).
Vermont: Vermont Quarantine List, Regulated Introduced Plant Species Rule (eff. June 16, 2026).
New Hampshire: New Hampshire Official Rare Plants List (Ncr 312, eff. Jan 1, 2020).
New Hampshire: NH Prohibited Invasive Species List (Agr 3800, Table 3800.1).
Connecticut: Connecticut Endangered, Threatened and Special Concern Plants (RCSA 26-306; 2015 list).
Connecticut: Connecticut prohibited invasive plants (Conn. Gen. Stat. § 22a-381d).
Idaho: Idaho noxious weeds (IDAPA 02.06.09, Section 220).
Rhode Island: Rhode Island Rare Plants 2016 (RI Natural History Survey, from the RI Wildlife Action Plan; informational, Rhode Island has no state plant-protection listing law).
Iowa: Iowa endangered, threatened and special concern plants (Iowa Admin. Code r. 571-77.3).
Iowa: Iowa noxious weeds (Iowa Code § 317.1A).
South Dakota: South Dakota statewide noxious weeds (ARSD 12:62:03:01.06).
Delaware: Rare and Uncommon Plants of Delaware (DNREC, 2024; informational, Delaware has no state plant-protection list).
Delaware: Delaware Invasive Plant List (3 Del. Admin. Code § 806-3.0).
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 vulgare (global and state ranks).
Edibility and toxicity: NC State Extension.
Photo: laiet17 via iNaturalist · CC0 · resized.