Epilobium palustreL.

marsh willowherb

WFO wfo-0000669541 Accepted WFO 2026-06 8 photographs CC BY

Plate 1 figs. a–h · 8 separate observations

Epilobium palustre, photographed by Вячеслав Юсупов
fig. a Вячеслав Юсупов, CC BY 4.0 / 2021-10-05 / obs. 162302213

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 107 botanical countries

Regions where Epilobium palustre is native: Afghanistan, Altay, Amur, Buryatiya, China North-Central, China South-Central, China Southeast, Chita, Inner Mongolia, Iran, Irkutsk, Japan, Kamchatka, Kazakhstan, Khabarovsk, Kirgizstan, Korea, Krasnoyarsk, Kuril Is., Magadan, Manchuria, North Caucasus, Primorye, Qinghai, Sakhalin, Tadzhikistan, Tibet, Transcaucasus, Türkiye, Tuva, Uzbekistan, West Siberia, Xinjiang, Yakutiya, East Himalaya, Nepal, West Himalaya, Albania, Austria, Baltic States, Belarus, Belgium, Bulgaria, Central European Russia, Czechia-Slovakia, Denmark, East European Russia, Finland, Føroyar, France, Germany, Great Britain, Greece, Hungary, Iceland, Ireland, Italy, Krym, Netherlands, North European Russia, Northwest European Russia, Norway, NW. Balkan Pen., Poland, Romania, South European Russia, Spain, Sweden, Switzerland, Ukraine, Alaska, Alberta, British Columbia, California, Colorado, Connecticut, Greenland, Idaho, Labrador, Maine, Manitoba, Massachusetts, Michigan, Minnesota, Montana, New Brunswick, New Hampshire, New Jersey, New Mexico, New York, Newfoundland, Northwest Territories, Nova Scotia, Nunavut, Ontario, Oregon, Pennsylvania, Prince Edward I., Québec, Rhode I., Saskatchewan, South Dakota, Utah, Vermont, Wisconsin, Wyoming, Yukon AfghanistanAltayAmurBuryatiyaChina North-CentralChina South-CentralChina SoutheastChitaInner MongoliaIranIrkutskJapanKamchatkaKazakhstanKhabarovskKirgizstanKrasnoyarskMagadanManchuriaNorth CaucasusPrimoryeQinghaiSakhalinTadzhikistanTibetTranscaucasusTürkiyeTuvaUzbekistanWest SiberiaXinjiangYakutiyaEast HimalayaNepalWest HimalayaAlbaniaAustriaBaltic StatesBelarusBelgiumBulgariaCentral European RussiaCzechia-SlovakiaDenmarkEast European RussiaFinlandFranceGermanyGreeceHungaryIcelandIrelandItalyKrymNetherlandsNorth European RussiaNorthwest European RussiaNorwayNW. Balkan Pen.PolandRomaniaSouth European RussiaSpainSwedenSwitzerlandUkraineAlaskaAlbertaBritish ColumbiaCaliforniaColoradoConnecticutGreenlandIdahoLabradorMaineManitobaMassachusettsMichiganMinnesotaMontanaNew BrunswickNew HampshireNew JerseyNew MexicoNew YorkNewfoundlandNorthwest TerritoriesNova ScotiaNunavutOntarioOregonPennsylvaniaPrince Edward I.QuébecSaskatchewanSouth DakotaUtahVermontWisconsinWyomingYukon KoreaFøroyarRhode I.
Native distribution of Epilobium palustre, 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. Regions too small to draw at this scale are marked with a dot.
RegionTDWG codeContinent
Alaska ASK NORTHERN AMERICA
Alberta ABT
British Columbia BRC
California CAL
Colorado COL
Connecticut CNT
Greenland GNL
Idaho IDA
Labrador LAB
Maine MAI
Manitoba MAN
Massachusetts MAS
Michigan MIC
Minnesota MIN
Montana MNT
New Brunswick NBR
New Hampshire NWH
New Jersey NWJ
New Mexico NWM
New York NWY
Newfoundland NFL
Northwest Territories NWT
Nova Scotia NSC
Nunavut NUN
Ontario ONT
Oregon ORE
Pennsylvania PEN
Prince Edward I. PEI
Québec QUE
Rhode I. RHO
Saskatchewan SAS
South Dakota SDA
Utah UTA
Vermont VER
Wisconsin WIS
Wyoming WYO
Yukon YUK
Afghanistan AFG ASIA-TEMPERATE
Altay ALT
Amur AMU
Buryatiya BRY
China North-Central CHN
China South-Central CHC
China Southeast CHS
Chita CTA
Inner Mongolia CHI
Iran IRN
Irkutsk IRK
Japan JAP
Kamchatka KAM
Kazakhstan KAZ
Khabarovsk KHA
Kirgizstan KGZ
Korea KOR
Krasnoyarsk KRA
Kuril Is. KUR
Magadan MAG
Manchuria CHM
North Caucasus NCS
Primorye PRM
Qinghai CHQ
Sakhalin SAK
Tadzhikistan TZK
Tibet CHT
Transcaucasus TCS
Türkiye TUR
Tuva TVA
Uzbekistan UZB
West Siberia WSB
Xinjiang CHX
Yakutiya YAK
Albania ALB EUROPE
Austria AUT
Baltic States BLT
Belarus BLR
Belgium BGM
Bulgaria BUL
Central European Russia RUC
Czechia-Slovakia CZE
Denmark DEN
East European Russia RUE
Finland FIN
Føroyar FOR
France FRA
Germany GER
Great Britain GRB
Greece GRC
Hungary HUN
Iceland ICE
Ireland IRE
Italy ITA
Krym KRY
Netherlands NET
North European Russia RUN
Northwest European Russia RUW
Norway NOR
NW. Balkan Pen. YUG
Poland POL
Romania ROM
South European Russia RUS
Spain SPA
Sweden SWE
Switzerland SWI
Ukraine UKR
East Himalaya EHM ASIA-TROPICAL
Nepal NEP
West Himalaya WHM

Not drawn on the map: Kuril Is., Great Britain. We hold no public-domain boundary for these regions, so they are 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.

Flowering 124 in flower of 134 examined

Proportion of examined Epilobium palustre in flower, by month
Month In flower Examined Share 95% interval
Jan 0 0 too few examined
Feb 0 0 too few examined
Mar 0 0 too few examined
Apr 0 0 too few examined
May 0 0 too few examined
Jun 4 5 80% 38% to 96%
Jul 58 60 97% 89% to 99%
Aug 56 60 93% 84% to 97%
Sep 5 7 71% 36% to 92%
Oct 1 2 too few examined
Nov 0 0 too few examined
Dec 0 0 too few examined

Peak flowering in Jul. Each bar is the share of Epilobium palustre observations in which someone actually recorded the reproductive state and found the plant in flower, not the raw number of flowering records. That distinction matters: people observe plants far more in spring than in winter, so a bare count of flowering records partly measures when people go outside. Dividing by the number examined removes that. 124 of 134 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. 8 months have fewer than 5 examined observations, so no proportion is drawn for them. This is still a global aggregate and not a forecast for your garden: the same species flowers on different dates in different hemispheres. Where a species has fewer than 30 flowering records we do not draw this chart at all. Computed from 10.15468/dl.cgje2x.

Where it actually grows measured, from 2,008 observations

Condition 5th percentile Median 95th percentile
Coldest month, mean daily low -26.5 °C -12.0 °C 0.0 °C
Warmest month, mean daily high 14.9 °C 22.5 °C 24.4 °C
Annual rainfall 384 mm 656 mm 1,572 mm
Rainfall in the driest quarter 32 mm 103 mm 287 mm

It is found where winters are arctic. This is not care advice and it is not a forecast. It is a measurement: we sampled the climate at every one of the 2,008 research-grade observations of Epilobium palustre 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. Climate from CHELSA V2.1 (Karger et al. 2017); occurrences from 10.15468/dl.cgje2x.

Also published as 77 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.

  • Chamaenerion americanum Sweet
  • Chamaenerion palustre (L.) Scop.
  • Chamaenerion palustre (L.) Schreb.
  • Epilobium alpinum L.
  • Epilobium alpinum var. gavei H.Lév.
  • Epilobium alpinum var. majus Hartm.
  • Epilobium alpinum var. minus Hartm.
  • Epilobium alsineifolium Wirtg. ex Hausskn.
  • Epilobium clavatotrichon (Rohlena) A.W.Hill
  • Epilobium empetrifolium Kunze ex Hausskn.
  • Epilobium fischerianum (Hausskn.) Pavlov
  • Epilobium kerneri Borbás
  • Epilobium ligulatum Baker
  • Epilobium lineare Muhl.
  • Epilobium lineare f. angustissimum Hausskn.
  • Epilobium lineare f. latifolium E.L.Rand & Redfield
  • Epilobium lineare f. pennsylvanicum Hausskn.
  • Epilobium lineare f. simplex Hausskn.
  • Epilobium lineare var. oliganthum (Michx.) Trel.
  • Epilobium molle var. sabulonense Fernald
  • Epilobium nesophilum var. lupulinum Hodgdon & R.B.Pike
  • Epilobium nesophilum var. sabulonense (Fernald) Fernald
  • Epilobium nutans Kern.
  • Epilobium oliganthum Michx.

and 53 more.

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.