Potamogeton compressusL.

grass-wrack pondweed

WFO wfo-0000769769 Accepted WFO 2026-06 8 photographs CC BY

Plate 1 figs. a–h · 8 separate observations

Potamogeton compressus, photographed by Dmitriy Bochkov
fig. a Dmitriy Bochkov, CC BY 4.0 / 2019-07-09 / obs. 44505653
Potamogeton compressus, photographed by Ivan Bashinskiy
fig. b Ivan Bashinskiy, CC BY 4.0 / obs. 58231771
Potamogeton compressus, photographed by Daria Melnikova
fig. c Daria Melnikova, CC BY 4.0 / obs. 48759901
Potamogeton compressus, photographed by Andre Hosper
fig. d Andre Hosper, CC BY 4.0 / obs. 41614496
Potamogeton compressus, photographed by Oleg Kosterin
fig. e Oleg Kosterin, CC BY 4.0 / obs. 172738624
Potamogeton compressus, photographed by Nadezhda Kiseleva
fig. f Nadezhda Kiseleva, CC BY 4.0 / obs. 167539698
Potamogeton compressus, photographed by Dmitriy Bochkov
fig. g Dmitriy Bochkov, CC BY 4.0 / obs. 44141273
Potamogeton compressus, photographed by Павлик Лисицын
fig. h Павлик Лисицын, CC BY 4.0 / obs. 151186384

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 38 botanical countries

Regions where Potamogeton compressus is native: Altay, Amur, Buryatiya, China South-Central, Chita, Irkutsk, Japan, Kamchatka, Kazakhstan, Khabarovsk, Krasnoyarsk, Mongolia, West Siberia, Yakutiya, Austria, Baltic States, Belarus, Belgium, Central European Russia, Czechia-Slovakia, Denmark, East European Russia, Finland, France, Germany, Great Britain, Greece, Netherlands, North European Russia, Northwest European Russia, Norway, NW. Balkan Pen., Poland, South European Russia, Spain, Sweden, Switzerland, Ukraine AltayAmurBuryatiyaChina South-CentralChitaIrkutskJapanKamchatkaKazakhstanKhabarovskKrasnoyarskMongoliaWest SiberiaYakutiyaAustriaBaltic StatesBelarusBelgiumCentral European RussiaCzechia-SlovakiaDenmarkEast European RussiaFinlandFranceGermanyGreeceNetherlandsNorth European RussiaNorthwest European RussiaNorwayNW. Balkan Pen.PolandSouth European RussiaSpainSwedenSwitzerlandUkraine
Native distribution of Potamogeton compressus, 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
Austria AUT EUROPE
Baltic States BLT
Belarus BLR
Belgium BGM
Central European Russia RUC
Czechia-Slovakia CZE
Denmark DEN
East European Russia RUE
Finland FIN
France FRA
Germany GER
Great Britain GRB
Greece GRC
Netherlands NET
North European Russia RUN
Northwest European Russia RUW
Norway NOR
NW. Balkan Pen. YUG
Poland POL
South European Russia RUS
Spain SPA
Sweden SWE
Switzerland SWI
Ukraine UKR
Altay ALT ASIA-TEMPERATE
Amur AMU
Buryatiya BRY
China South-Central CHC
Chita CTA
Irkutsk IRK
Japan JAP
Kamchatka KAM
Kazakhstan KAZ
Khabarovsk KHA
Krasnoyarsk KRA
Mongolia MON
West Siberia WSB
Yakutiya YAK

Not drawn on the map: Great Britain. 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 86 observations

Condition 5th percentile Median 95th percentile
Coldest month, mean daily low -19.6 °C -11.1 °C -2.4 °C
Warmest month, mean daily high 20.6 °C 22.9 °C 25.0 °C
Annual rainfall 373 mm 660 mm 751 mm
Rainfall in the driest quarter 47 mm 103 mm 126 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 86 research-grade observations of Potamogeton compressus 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 19 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 acutifolius Hornem.
  • Potamogeton acutifolius f. major (Fieber) Rchb.
  • Potamogeton acutifolius var. major Fieber
  • Potamogeton complanatus Willd.
  • Potamogeton compressus var. acutus Schltdl.
  • Potamogeton compressus var. dimidius Crép.
  • Potamogeton compressus var. obtusus Schltdl.
  • Potamogeton crispus var. major Gray
  • Potamogeton crispus var. oppositifolius Gray
  • Potamogeton cuspidatus Schrad.
  • Potamogeton monoginus Miki
  • Potamogeton reflexus A.Benn.
  • Potamogeton zosterifolius Schumach.
  • Potamogeton zosterifolius f. magnus Tiselius
  • Potamogeton zosterifolius f. selenocarpus Hagstr.
  • Potamogeton zosterifolius var. americanus A.Benn.
  • Potamogeton zosterifolius var. minor Hook.
  • Potamogeton zosterophyllus Dumort.
  • Spirillus zosterifolius (Schumach.) 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.