
Flower profile
Low smartweed
Persicaria longiseta
Low smartweed is a wildflower that USDA PLANTS lists as introduced in the lower 48 states. It's on our flower lists for 22 states, and across the U.S. it's most often seen in bloom in June–October.
*iNaturalist research-grade observations, as of October 17, 2026.
On our lists for: Alabama, Arkansas, Connecticut, Delaware, Georgia, Illinois, Indiana, Iowa, Kentucky, Maryland, Massachusetts, Missouri, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Rhode Island, South Carolina, Tennessee, Virginia, West Virginia
Quick look
Persicaria longiseta is a species of flowering plant in the knotweed family known by the common names Oriental lady's thumb, bristly lady's thumb, Asiatic smartweed, long-bristled smartweed, low smartweed, Asiatic waterpepper, bristled knotweed, bunchy knotweed, and tufted knotweed. It is native to Asia, and it is present in North America and Europe as an introduced species and often a weed.
- It belongs to the Polygonaceae family. iNaturalist
- USDA PLANTS describes it as an herb (forb) with a annual life cycle. USDA PLANTS
- USDA PLANTS lists it as introduced in the lower 48 states and records it in 34 states. USDA PLANTS
- In New York, most iNaturalist sightings of it in flower come in June–November. iNaturalist
- In Pennsylvania, most iNaturalist sightings of it in flower come in June–October. iNaturalist
- iNaturalist has 4,636 research-grade sightings of it in New York, ranking #45 among the 109 flowers on our New York list. iNaturalist
- iNaturalist has 4,152 research-grade sightings of it in Pennsylvania, ranking #42 among the 111 flowers on our Pennsylvania list. iNaturalist
- iNaturalist has 3,639 research-grade sightings of it in Virginia, ranking #44 among the 110 flowers on our Virginia list. iNaturalist
Low smartweed gift ideas
Handmade low smartweed gifts from independent makers.
🌱 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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Low smartweed art print
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Low smartweed greeting card
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Low smartweed mug
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Low smartweed earrings
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Low smartweed embroidery pattern
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Low smartweed sticker
When does it bloom?
Bloom time in each of our 22 states
| State | Type | Peak bloom | Sightings* |
|---|---|---|---|
| New York | Introduced | June–November | 4,636 |
| Pennsylvania | Introduced | June–October | 4,152 |
| Virginia | Introduced | July–October | 3,639 |
| North Carolina | Introduced | July–October | 3,586 |
| Ohio | Introduced | June–October | 3,207 |
| Maryland | Introduced | May–October | 2,957 |
| New Jersey | Introduced | June–November | 2,863 |
| Massachusetts | Introduced | June–October | 2,475 |
| Illinois | Introduced | June–October | 1,962 |
| Tennessee | Introduced | July–October | 1,906 |
| Indiana | Introduced | July–October | 1,725 |
| Missouri | Introduced | May–October | 1,445 |
| Georgia | Introduced | May–November | 1,418 |
| Kentucky | Introduced | May–November | 989 |
| Alabama | Introduced | May–October | 986 |
| Connecticut | Introduced | June–October | 963 |
| Arkansas | Introduced | May–October | 854 |
| West Virginia | Introduced | July–October | 547 |
| South Carolina | Introduced | few records | 513 |
| Delaware | Introduced | few records | 441 |
| Iowa | Introduced | few records | 389 |
| Rhode Island | – | few records | 303 |
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
- 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
- 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
- North Carolina
- Not listed Not on North Carolina Protected Plant Species List (02 NCAC 48F .0301). NatureServe: SNA, not applicable (usually because it isn't native there) in North Carolina. 02 NCAC 48F .0301
- 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
- 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
- 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
- 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
- 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
- Tennessee
- Not listed Not on Tennessee endangered plants (Tenn. Comp. R. & Regs. 0400-06-02-.04, Rare Plant Protection and Conservation Act). NatureServe: SNA, not applicable (usually because it isn't native there) in Tennessee. TN rule 0400-06-02-.04
- Indiana
- No list Indiana has no state law listing endangered or threatened plants (the DNR keeps a rare plant list, but it isn't regulatory), so we show NatureServe's Indiana ranks instead. NatureServe: SNA, not applicable (usually because it isn't native there) in Indiana.
- 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
- Georgia
- Not listed Not on Georgia protected plants (Ga. Comp. R. & Regs. 391-4-10-.09; a 2026 update is proposed). NatureServe: SNA, not applicable (usually because it isn't native there) in Georgia. Ga. R. 391-4-10-.09
- Kentucky
- Not listed Not on Kentucky endangered and threatened plant lists (400 KAR 3:040, eff. 2026). NatureServe: SNA, not applicable (usually because it isn't native there) in Kentucky. 400 KAR 3:040
- Alabama
- No list Alabama has no state law listing endangered or threatened plants, so we show NatureServe's Alabama ranks instead. NatureServe: SNA, not applicable (usually because it isn't native there) in Alabama.
- 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
- 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.
- 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.
- South Carolina
- No list South Carolina has no state law listing endangered or threatened plants, so we show NatureServe's South Carolina ranks instead. NatureServe: SNA, not applicable (usually because it isn't native there) in South Carolina.
- 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
- 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
- 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 has no Rhode Island rank for it. RI rare plants 2016
- 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?
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.
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 low smartweed in 34 states plus Washington, D.C.
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, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Nebraska, New Hampshire, New Jersey, New Mexico, New York, North Carolina, Ohio, Pennsylvania, South Carolina, Tennessee, Texas, Vermont, Virginia, West Virginia, Wisconsin; District of Columbia.
New York counties with USDA records: Albany, Bronx, Chemung, Delaware, Dutchess, Greene, Kings, Nassau, New York, Oneida, Onondaga, Orange, Putnam, Queens, Rensselaer, Richmond, Rockland, Saratoga, Schuyler, Suffolk, Tompkins, Ulster, Warren, Westchester.
Pennsylvania counties with USDA records: Adams, Allegheny, Armstrong, Beaver, Bedford, Berks, Blair, Bradford, Bucks, Butler, Centre, Chester, Clarion, Clinton, Cumberland, Dauphin, Delaware, Erie, Fayette, Franklin, Fulton, Indiana, Juniata, Lackawanna, Lancaster, Lehigh, Luzerne, Monroe, Montgomery, Northampton, Perry, Philadelphia, Pike, Venango, Warren, Washington, Wayne, Westmoreland, Wyoming, York.
Virginia counties with USDA records: Accomack, Albemarle, Amelia, Amherst, Appomattox, Arlington, Augusta, Bath, Bedford, Bland, Botetourt, Buckingham, Campbell, Caroline, Charlotte, Chesapeake , Chesterfield, Clarke, Craig, Culpeper, Cumberland, Dickenson, Essex, Fairfax, Fauquier, Fluvanna, Franklin, Frederick, Giles, Gloucester, Goochland, Grayson, Greene, Halifax, Hanover, Henrico, Henry, Isle of Wight, James City, King George, King William, Lee, Loudoun, Louisa, Madison, Mecklenburg, Middlesex, Montgomery, Nelson, Newport News , Northampton, Orange, Page, Patrick, Pittsylvania, Powhatan, Prince Edward, Prince George, Prince William, Pulaski, Rappahannock, Rockbridge, Rockingham, Russell, Scott, Shenandoah, Smyth, Spotsylvania, Stafford, Suffolk , Surry, Sussex, Tazewell, Warren, Westmoreland, Wise, York.
More New York flowers
Sources
- USDA, NRCS. PLANTS Database, profile POCEL.
- iNaturalist, Persicaria longiseta: taxonomy, research-grade observation counts and “Flowering” annotations, retrieved October 17, 2026.
- Wikipedia, Persicaria longiseta (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).
- 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).
- Virginia: Virginia endangered and threatened plant and insect species (2VAC5-320-10).
- Virginia: Virginia noxious weeds (2VAC5-317-20, Tier 1, 2 and 3).
- North Carolina: North Carolina Protected Plant Species List (02 NCAC 48F .0301).
- North Carolina: North Carolina Noxious Weed List (02 NCAC 48A .1702) (the list names any non-native Lythrum; we apply it to purple loosestrife (Lythrum salicaria), which isn't native).
- 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).
- 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).
- 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).
- 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.).
- 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).
- Tennessee: Tennessee endangered plants (Tenn. Comp. R. & Regs. 0400-06-02-.04, Rare Plant Protection and Conservation Act).
- Tennessee: Tennessee Pest Plant List (Tenn. Comp. R. & Regs. 0080-06-24-.02).
- Indiana: Indiana prohibited invasive terrestrial plants (312 IAC 18-3-25).
- Missouri: Missouri Wildlife Code endangered species (3 CSR 10-4.111), plants.
- Missouri: Missouri noxious weed list (2 CSR 70-45.005).
- Georgia: Georgia protected plants (Ga. Comp. R. & Regs. 391-4-10-.09; a 2026 update is proposed).
- Kentucky: Kentucky endangered and threatened plant lists (400 KAR 3:040, eff. 2026).
- Kentucky: Kentucky noxious weeds and invasive plants on state rights-of-way (KRS 176.051; species list from the Kentucky Transportation Cabinet).
- Alabama: Alabama noxious weeds (Ala. Admin. Code r. 80-10-14-.04).
- Connecticut: Connecticut Endangered, Threatened and Special Concern Plants (RCSA 26-306; 2015 list).
- Connecticut: Connecticut prohibited invasive plants (Conn. Gen. Stat. § 22a-381d).
- Arkansas: Arkansas State Plant Board noxious weeds and prohibited plants (2 CAR § 50-101).
- 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).
- South Carolina: South Carolina State Plant Pest List, plants (S.C. Code Regs. 27-135; Clemson Dept. of Plant Industry).
- 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).
- Iowa: Iowa endangered, threatened and special concern plants (Iowa Admin. Code r. 571-77.3).
- Iowa: Iowa noxious weeds (Iowa Code § 317.1A).
- 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).
- USFWS, ECOS species database (ESA listing check), October 17, 2026.
- NatureServe Explorer, Persicaria longiseta (global and state ranks).
- Edibility and toxicity: no source found (marked "not well documented").
- Photo: Jonathan Layman via iNaturalist · CC BY 4.0 · resized.


