water smartweed

(Persicaria amphibia)

Conservation Status
water smartweed
  IUCN Red List

LC - Least Concern


N5 - Secure

SNR - Unranked


not listed

Wetland Indicator Status
  Great Plains

OBL - Obligate wetland


OBL - Obligate wetland

  Northcentral & Northeast

OBL - Obligate wetland


Water smartweed may be floating on water (aquatic), rising out of standing water (emergent), or growing in periodically inundated or merely permanently moist areas (terrestrial).

The upper surface of the leaves are shiny.

The inflorescence is long and is interrupted near the base. The flowers are pink to red.




12 to 60


Flower Color


Pink to red


Similar Species


Wet to moist. Meadows, pond edges, marshes.




June to September


Pests and Diseases






Distribution Map



2, 3, 4, 5, 7, 24, 28, 29, 30.








Common and widespread

  Kingdom Plantae (green algae and land plants)  
  Subkingdom Viridiplantae (green plants)  
  Infrakingdom Streptophyta (land plants and green algae)  
  Superdivision Embryophyta (land plants)  
  Division Tracheophyta (vascular plants)  
  Subdivision Spermatophytina (seed plants)  
  Class Magnoliopsida (flowering plants)  
  Superorder Caryophyllanae  


Caryophyllales (pinks, cactuses, and allies)  


Polygonaceae (knotweed)  
  Subfamily Polygonoideae  
  Tribe Persicarieae  
  Subtribe Persicariinae  


Persicaria (knotweeds, smartweeds, and waterpeppers)  

Subordinate Taxa


Most botanists recognize two North American varieties and one Eurasian variety. Others contend that the characters used to define the varieties, when including the Eurasian phenotype, form a continuous morphological gradation (cline), making recognition of the varieties untenable.


flanged smartweed (Persicaria amphibia var. stipulaceum)

longroot smartweed (Persicaria amphibia var. emersum)

water smartweed (Persicaria amphibia var. amphibia)




Persicaria amphibia var. emersa

Persicaria amphibia var. stipulacea

Persicaria coccinea

Persicaria mesochora

Persicaria muehlenbergii

Persicaria muhlenbergii

Persicaria nebraskensis

Polygonum amphibium

Polygonum amphibium ssp. laevimarginatum

Polygonum amphibium var. coccineum

Polygonum amphibium var. emersum

Polygonum amphibium var. hartwrightii

Polygonum amphibium var. stipulaceum

Polygonum coccineum

Polygonum coccineum var. pratincola

Polygonum coccineum var. rigidulum

Polygonum coccineum var. terrestre

Polygonum fluitans

Polygonum hartwrightii

Polygonum inundatum

Polygonum muehlenbergii

Polygonum muehlenbergii var. terrestre

Polygonum muhlenbergii

Polygonum natans


Common Names


water knotweed

water persicaria

water smartweed












Visitor Photos

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Growing near a creek

    water smartweed      



… growing in wetland, edge of my pond

    water smartweed   water smartweed  
    water smartweed      
MinnesotaSeasons.com Photos


    water smartweed      


    water smartweed   water smartweed  
    water smartweed   water smartweed  


    water smartweed   water smartweed  
    water smartweed   water smartweed  
    water smartweed      


    water smartweed   water smartweed  


    water smartweed   water smartweed  



  Polygonum amphibium stipulaceum WATER KNOTWEED
Frank Mayfield
  Polygonum amphibium stipulaceum WATER KNOTWEED  



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Other Videos
  Water Knotweed (Persicaria amphibia, synoniem: Polygonum amphibium) - 2012-08-04

Published on Aug 7, 2012

Persicaria amphibia (syn. Polygonum amphibium) is a species of flowering plant in the knotweed family known by several common names, including water knotweed, water smartweed, and amphibious bistort.

Veenwortel (Persicaria amphibia, synoniem: Polygonum amphibium) is een plant uit de duizendknoopfamilie (Polygonaceae).




Visitor Sightings

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Location: Savage, MN

Growing near a creek

swamp smartweed  

Location: Lake Shore

… growing in wetland, edge of my pond

swamp smartweed  
MinnesotaSeasons.com Sightings

Baker Park Reserve

Belgium Prairie

Blaine Wetland Sanctuary

Bur Oak WMA

Butternut Valley Prairie SNA

Clifton E. French Regional Park

Clinton Prairie SNA

Compass Prairie SNA

Cottonwood River Prairie SNA

Crosby Farm Regional Park

Crow-Hassan Park Reserve

Des Moines River SNA

Felton Prairie SNA, Bicentennial Unit

Felton Prairie SNA, Shrike Unit

Foxhome Prairie

Glacial Lakes State Park

Glendalough State Park

Glynn Prairie SNA

Hastings SNA

Hole-in-the-Mountain Prairie

Holthe Prairie SNA

Hyland Lake Park Reserve

Hythecker Prairie SNA

Jensen Memorial WMA

John Peter Hoffman Spring Brook Valley WMA

Joseph A. Tauer Prairie SNA

Kasota Prairie

Kettledrummer Prairie

Lake Alexander Woods SNA, South Unit

Lake Elmo Park Reserve

Langhei Prairie SNA

Lebanon Hills Regional Park

Leif Mountain

Lester Lake SNA

Malmberg Prairie SNA

Margherita Preserve-Audubon Prairie

Miller Prairie, West Unit

Minnesota Valley NWR, Chaska Unit

Minnesota Valley NWR, Louisville Swamp Unit

Minnesota Valley NWR, Rapids Lake Unit

Minnesota Valley NWR, Wilkie Unit

Mound Spring Prairie SNA, North Unit

Myre-Big Island State Park

Northern Tallgrass Prairie NWR, Hoffman Unit

Northern Tallgrass Prairie NWR, Pavia Unit

Northern Tallgrass Prairie NWR, Rengstorf Unit

Northern Tallgrass Prairie NWR, Spieker Unit

Northern Tallgrass Prairie NWR, Touch the Sky Prairie Unit

Oronoco Prairie SNA

Otter Tail Prairie SNA

Pembina Trail Preserve SNA, Crookston Prairie Unit

Phelps Lake WMA

Pilot Knob

Pine Bend Bluffs SNA

Plover Prairie, East Unit

Potato Lake SNA

Prairie Coteau SNA

Prairie Creek WMA, Koester Prairie Unit

Prairie Smoke Dunes SNA

Red Rock Prairie

Richard M. & Mathilde Rice Elliott SNA

Sand Prairie Wildlife Management and Environmental Education Area

Sandpiper Prairie SNA

Santee Prairie SNA

Savage Fen SNA

Schaefer Prairie

Seven Sisters Prairie

Sheepberry Fen

Sibley State Park

Springbrook Nature Center

Staffanson Prairie

Swedes Forest SNA

Tribute WMA

Twin Valley Prairie Addition

Vermillion River WMA

Wahpeton Prairie WMA

Whitetail Woods Regional Park

Woodbury WMA

Yellow Bank Hills SNA







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