Potamogeton richardsoniiRydb.

Richardson's pondweed

WFO wfo-0000769973 Accepted WFO 2026-06 8 photographs CC0 / CC BY

Plate 1 figs. a–h · 8 separate observations

Potamogeton richardsonii, photographed by Allan Harris
fig. a Allan Harris, CC0 1.0 / 2021-10-02 / obs. 161065520
Potamogeton richardsonii, photographed by Victor Hooper
fig. b Victor Hooper, CC BY 4.0 / obs. 159950074
Potamogeton richardsonii, photographed by Andrew Sebastian
fig. c Andrew Sebastian, CC BY 4.0 / obs. 155187685
Potamogeton richardsonii, photographed by Steven Bodzin
fig. d Steven Bodzin, CC BY 4.0 / obs. 151284269
Potamogeton richardsonii, photographed by Doug Macaulay
fig. e Doug Macaulay, CC BY 4.0 / obs. 150701308
Potamogeton richardsonii, photographed by Mary Krieger
fig. f Mary Krieger, CC BY 4.0 / obs. 151694579
Potamogeton richardsonii, photographed by Eric Schmidt
fig. g Eric Schmidt, CC BY 4.0 / obs. 169038074
Potamogeton richardsonii, photographed by Eric Schmidt
fig. h Eric Schmidt, CC BY 4.0 / obs. 145208089

Every figure is a research-grade observation under CC0, CC BY or CC BY-SA, rehosted with the photographer’s name, the licence and the observation it came from. Photographs under a NonCommercial licence are excluded from this site and are never stored, which costs us a great many pictures and is not negotiable.

Native range 48 botanical countries

Regions where Potamogeton richardsonii is native: Kamchatka, Khabarovsk, Magadan, Primorye, Sakhalin, Yakutiya, Alaska, Alberta, Aleutian Is., British Columbia, California, Colorado, Connecticut, Idaho, Illinois, Indiana, Iowa, Labrador, Maine, Manitoba, Massachusetts, Michigan, Minnesota, Montana, Nebraska, Nevada, New Brunswick, New Hampshire, New Mexico, New York, Newfoundland, North Dakota, Northwest Territories, Nova Scotia, Nunavut, Ohio, Ontario, Oregon, Pennsylvania, Québec, Saskatchewan, South Dakota, Utah, Vermont, Washington, Wisconsin, Wyoming, Yukon KamchatkaKhabarovskMagadanPrimoryeSakhalinYakutiyaAlaskaAlbertaBritish ColumbiaCaliforniaColoradoConnecticutIdahoIllinoisIndianaIowaLabradorMaineManitobaMassachusettsMichiganMinnesotaMontanaNebraskaNevadaNew BrunswickNew HampshireNew MexicoNew YorkNewfoundlandNorth DakotaNorthwest TerritoriesNova ScotiaNunavutOhioOntarioOregonPennsylvaniaQuébecSaskatchewanSouth DakotaUtahVermontWashingtonWisconsinWyomingYukon
Native distribution of Potamogeton richardsonii, after Kew’s World Checklist of Vascular Plants. Introduced, extinct and doubtful records are excluded, so this is where the plant is from, not everywhere it now grows.
RegionTDWG codeContinent
Alaska ASK NORTHERN AMERICA
Alberta ABT
Aleutian Is. ALU
British Columbia BRC
California CAL
Colorado COL
Connecticut CNT
Idaho IDA
Illinois ILL
Indiana INI
Iowa IOW
Labrador LAB
Maine MAI
Manitoba MAN
Massachusetts MAS
Michigan MIC
Minnesota MIN
Montana MNT
Nebraska NEB
Nevada NEV
New Brunswick NBR
New Hampshire NWH
New Mexico NWM
New York NWY
Newfoundland NFL
North Dakota NDA
Northwest Territories NWT
Nova Scotia NSC
Nunavut NUN
Ohio OHI
Ontario ONT
Oregon ORE
Pennsylvania PEN
Québec QUE
Saskatchewan SAS
South Dakota SDA
Utah UTA
Vermont VER
Washington WAS
Wisconsin WIS
Wyoming WYO
Yukon YUK
Kamchatka KAM ASIA-TEMPERATE
Khabarovsk KHA
Magadan MAG
Primorye PRM
Sakhalin SAK
Yakutiya YAK

Not drawn on the map: Aleutian Is.. We hold no public-domain boundary for this region, so it is listed rather than guessed at.

Region boundaries approximated from Natural Earth (public domain) and mapped to TDWG World Geographical Scheme for Recording Plant Distributions (WGSRPD) level-3 botanical countries (Brummitt 2001). Indicative, not the official WGSRPD geometry.

Where it actually grows measured, from 1,110 observations

Condition 5th percentile Median 95th percentile
Coldest month, mean daily low -21.0 °C -12.9 °C -4.5 °C
Warmest month, mean daily high 19.8 °C 24.0 °C 27.7 °C
Annual rainfall 394 mm 859 mm 1,262 mm
Rainfall in the driest quarter 42 mm 130 mm 238 mm

It is found where winters are severely cold. This is not care advice and it is not a forecast. It is a measurement: we sampled the climate at every one of the 1,110 research-grade observations of Potamogeton richardsonii that carry a coordinate, and this is the range those places actually span. The 5th and 95th percentiles are used rather than the minimum and maximum, because a single cultivated specimen in a heated conservatory should not widen a tropical plant's range to the Arctic.

This is not a hardiness zone. A USDA zone is the average annual extreme minimum temperature. The figure above is the mean daily minimum of the coldest month, which is a different quantity and is typically far warmer. Reading one as the other would place a plant several zones too warm, so we do not publish a hardiness zone, because we do not have one.

Also published as 6 synonyms

A synonym is not an error. It is a record of botanists disagreeing, in print, about where this plant belongs. Each of these was somebody’s considered answer.

  • Potamogeton perfoliatus subsp. richardsonii (A.Benn.) Hultén
  • Potamogeton perfoliatus var. lanceolatus J.W.Robbins
  • Potamogeton perfoliatus var. richardsonii A.Benn.
  • Potamogeton perfoliatus var. sachalinensis H.Lév.
  • Potamogeton sachalinensis (H.Lév.) H.Lév.
  • Spirillus perfoliatus var. richardsonii (A.Benn.) Nieuwl.

Sourcesevery claim on this page

  1. World Flora Online Plant List. accepted name, authority, classification. CC0. Retrieved 2026-07-12.
  2. iNaturalist. photographs and flowering annotations, CC0 / CC BY / CC BY-SA only. per photograph. Retrieved 2026-06-27.
  3. Wikidata. common name (P1843), joined on the World Flora Online identifier (P7715). CC0. Retrieved 2026-07-13.
  4. Kew, World Checklist of Vascular Plants (WCVP v16). native distribution by TDWG level-3 botanical country, and life form. CC BY 3.0. Retrieved 2026-06-04.

We publish what we can source and we say so when we cannot. This page has no care advice and no toxicity claim, because we do not yet have those from a source we can cite.