Flower profile

Japanese barberry

Berberis thunbergii

Introduced in the lower 48

Japanese barberry is a flowering plant that USDA PLANTS lists as introduced in the lower 48 states. It's on our flower lists for 14 states, and across the U.S. it's most often seen in bloom in April–May.

32states

14of our state lists

48,848U.S. sightings*

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

On our lists for: Connecticut, Delaware, Maine, Maryland, Massachusetts, Michigan, New Jersey, New York, Ohio, Pennsylvania, Rhode Island, Vermont, Virginia, West Virginia

🚫

Regulated invasive plant in Pennsylvania, New York, Massachusetts, New Jersey, Maryland, Vermont, Maine, West Virginia and Delaware. It's on those states' official invasive plant lists (Pennsylvania: Class B noxious weed; New York: Prohibited invasive species (6 NYCRR § 575.3); Massachusetts: Prohibited plant (sale, import and propagation banned); New Jersey: Prohibited invasive plant (propagation banned from 2027, sale from 2030); Maryland: Prohibited invasive plant (some phase-outs run to 2028); Vermont: Quarantine List, Tier 3; Maine: Do Not Sell invasive plant (illegal to sell or import); West Virginia: Declared noxious weed; Delaware: Invasive Plant List (sale and propagation prohibited)). Please don't plant or share it there. ^{PA noxious weed list 6 NYCRR Part 575 MA Prohibited Plant List NJ prohibited invasive list MD prohibited invasive list Vermont Quarantine List Maine Do Not Sell list 61CSR14A 3 DE Admin. Code 806}

Quick look

Berberis thunbergii, the Japanese barberry, Thunberg's barberry, or red barberry, is a species of flowering plant in the barberry family Berberidaceae, native to Japan and eastern Asia, though widely naturalized in China and North America, where it has become a problematic invasive in many places, leading to declines in species diversity, increased tick habitat, and soil changes.
From Wikipedia's article Berberis thunbergii, CC BY-SA 4.0.

It belongs to the Berberidaceae family. ^iNaturalist
USDA PLANTS describes it as a shrub with a perennial life cycle. ^{USDA PLANTS}
USDA PLANTS lists it as introduced in the lower 48 states and records it in 32 states. ^{USDA PLANTS}
In Pennsylvania, most iNaturalist sightings of it in flower come in April–May. ^iNaturalist
In New York, most iNaturalist sightings of it in flower come in April–May. ^iNaturalist
USDA PLANTS lists its flower color as yellow. ^{USDA PLANTS}
USDA PLANTS gives its bloom period as late spring. ^{USDA PLANTS}
USDA PLANTS lists a mature height of about 6 ft. ^{USDA PLANTS}
iNaturalist has 6,602 research-grade sightings of it in Pennsylvania, ranking #16 among the 111 flowers on our Pennsylvania list. ^iNaturalist
iNaturalist has 5,537 research-grade sightings of it in New York, ranking #30 among the 109 flowers on our New York list. ^iNaturalist
iNaturalist has 4,890 research-grade sightings of it in Massachusetts, ranking #24 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”) (866 records)

Bloom time in each of our 14 states

State	Type	Peak bloom	Sightings*
Pennsylvania	Introduced	April–May	6,602
New York	Introduced	April–May	5,537
Massachusetts	Introduced	April–May	4,890
New Jersey	Introduced	April–May	4,870
Maryland	Introduced	April–May	4,216
Michigan	Introduced	April–June	3,543
Virginia	Introduced	March–April	2,985
Ohio	Introduced	April–May	2,391
Connecticut	Introduced	April–May	2,124
Vermont	Introduced	May	1,559
Maine	Introduced	May	1,100
West Virginia	Introduced	few records	856
Rhode Island	Introduced	few records	526
Delaware	Introduced	few records	168

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
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}
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}
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}
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}
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}
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}
Virginia: Not listed Not on Virginia endangered and threatened plant and insect species (2VAC5-320-10). NatureServe: SNA, not applicable (usually because it isn't native there) in Virginia. ^2VAC5-320-10
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}
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}
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}
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}
West Virginia: No list West Virginia has no state law listing endangered or threatened plants (only federally listed species are protected), so we show NatureServe's West Virginia ranks instead. NatureServe: SNA, not applicable (usually because it isn't native there) in West Virginia.
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}
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}
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 Japanese barberry in 32 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

Connecticut, Delaware, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky, Maine, Maryland, Massachusetts, Michigan, Minnesota, Missouri, Nebraska, New Hampshire, New Jersey, New York, North Carolina, North Dakota, Ohio, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Vermont, Virginia, Washington, West Virginia, Wisconsin, Wyoming; District of Columbia.

Pennsylvania counties with USDA records: Adams, Allegheny, Beaver, Bedford, Berks, Blair, Bradford, Bucks, Butler, Cambria, Carbon, Centre, Chester, Clearfield, Clinton, Columbia, Cumberland, Dauphin, Delaware, Elk, Erie, Fulton, Greene, Huntingdon, Indiana, Juniata, Lackawanna, Lancaster, Lawrence, Lebanon, Lehigh, Luzerne, Lycoming, McKean, Mercer, Mifflin, Monroe, Montgomery, Northampton, Northumberland, Pike, Snyder, Somerset, Susquehanna, Tioga, Venango, Warren, Wayne, Westmoreland, Wyoming, York.

New York counties with USDA records: Albany, Bronx, Cattaraugus, Chautauqua, Clinton, Dutchess, Erie, Essex, Genesee, Kings, Livingston, Nassau, New York, Oneida, Onondaga, Orange, Orleans, Putnam, Queens, Richmond, Rockland, Saratoga, Suffolk, Sullivan, Tompkins, Ulster, Westchester.

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

More Pennsylvania flowers

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Leatherleaf mahonia

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Twinleaf

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🌼 Blooms: March–April

Sources

USDA, NRCS. PLANTS Database, profile BETH.
iNaturalist, Berberis thunbergii: taxonomy, research-grade observation counts and “Flowering” annotations, retrieved October 17, 2026.
Wikipedia, Berberis thunbergii (lead quoted under CC BY-SA 4.0).
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).
New York: New York protected native plants (6 NYCRR § 193.3).
New York: New York prohibited and regulated invasive species (6 NYCRR Part 575).
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.).
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).
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).
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.
Virginia: Virginia endangered and threatened plant and insect species (2VAC5-320-10).
Virginia: Virginia noxious weeds (2VAC5-317-20, Tier 1, 2 and 3).
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).
Connecticut: Connecticut Endangered, Threatened and Special Concern Plants (RCSA 26-306; 2015 list).
Connecticut: Connecticut prohibited invasive plants (Conn. Gen. Stat. § 22a-381d).
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).
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).
West Virginia: West Virginia noxious weeds (W. Va. Code R. § 61-14A-5) (the rule abbreviates some names (e.g. “P. cuspidatum”); we expand them to match).
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).
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).
USFWS, ECOS species database (ESA listing check), October 17, 2026.
NatureServe Explorer, Berberis thunbergii (global and state ranks).
Edibility and toxicity: NC State Extension.
Photo: Shirley Zundell via iNaturalist · CC BY 4.0 · resized.