Lycopus uniflorusMichx.

northern bugleweed

WFO wfo-0000231468 Accepted WFO 2026-06 8 photographs CC0 / CC BY

Plate 1 figs. a–h · 8 separate observations

Lycopus uniflorus, photographed by Ryan Sorrells
fig. a Ryan Sorrells, CC BY 4.0 / 2021-10-17 / obs. 165289178

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.

The specimen a real sheet, in a real collection

Herbarium
The New York Botanical Garden
Accession
01157920
Filed as
Lycopus uniflorus Michx.
Det. by
D. E. Atha 2000-01-01
Collected
D. E. Atha 2000-08-17
Origin
US
The sheet
View the digitised specimen (CC BY 4.0)

A real pressed plant, in a real collection, under the accession number above. Not an illustration of one. The holding institution does not serve this sheet’s image to third parties, so there is no photograph here. The record is real and the link goes to it. Where we hold no openly licensed sheet for a species this section is simply absent, and where a sheet never recorded who determined it, that field stays empty rather than being filled in. Roughly half of all herbarium sheets never recorded a determiner, which is ordinary.

Native range 45 botanical countries

Regions where Lycopus uniflorus is native: Amur, Japan, Kamchatka, Khabarovsk, Korea, Kuril Is., Manchuria, Primorye, Sakhalin, Alaska, Alberta, Arkansas, British Columbia, California, Colorado, Connecticut, Idaho, Illinois, Iowa, Kansas, Kentucky, Labrador, Maine, Manitoba, Maryland, Michigan, Minnesota, Missouri, Montana, Nebraska, New Hampshire, New York, Newfoundland, North Carolina, North Dakota, Northwest Territories, Ontario, Québec, Rhode I., Saskatchewan, Tennessee, Vermont, Virginia, Wyoming, Yukon AmurJapanKamchatkaKhabarovskManchuriaPrimoryeSakhalinAlaskaAlbertaArkansasBritish ColumbiaCaliforniaColoradoConnecticutIdahoIllinoisIowaKansasKentuckyLabradorMaineManitobaMarylandMichiganMinnesotaMissouriMontanaNebraskaNew HampshireNew YorkNewfoundlandNorth CarolinaNorth DakotaNorthwest TerritoriesOntarioQuébecSaskatchewanTennesseeVermontVirginiaWyomingYukon KoreaRhode I.
Native distribution of Lycopus uniflorus, 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
Arkansas ARK
British Columbia BRC
California CAL
Colorado COL
Connecticut CNT
Idaho IDA
Illinois ILL
Iowa IOW
Kansas KAN
Kentucky KTY
Labrador LAB
Maine MAI
Manitoba MAN
Maryland MRY
Michigan MIC
Minnesota MIN
Missouri MSO
Montana MNT
Nebraska NEB
New Hampshire NWH
New York NWY
Newfoundland NFL
North Carolina NCA
North Dakota NDA
Northwest Territories NWT
Ontario ONT
Québec QUE
Rhode I. RHO
Saskatchewan SAS
Tennessee TEN
Vermont VER
Virginia VRG
Wyoming WYO
Yukon YUK
Amur AMU ASIA-TEMPERATE
Japan JAP
Kamchatka KAM
Khabarovsk KHA
Korea KOR
Kuril Is. KUR
Manchuria CHM
Primorye PRM
Sakhalin SAK

Not drawn on the map: Kuril 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.

Flowering 290 in flower of 331 examined

Proportion of examined Lycopus uniflorus 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 1 too few examined
Jun 0 4 too few examined
Jul 57 62 92% 82% to 97%
Aug 182 187 97% 94% to 99%
Sep 48 58 83% 71% to 90%
Oct 3 18 17% 6% to 39%
Nov 0 1 too few examined
Dec 0 0 too few examined

Peak flowering in Aug. Each bar is the share of Lycopus uniflorus 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. 290 of 331 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 1,981 observations

Condition 5th percentile Median 95th percentile
Coldest month, mean daily low -18.0 °C -11.6 °C 0.7 °C
Warmest month, mean daily high 19.7 °C 24.6 °C 29.0 °C
Annual rainfall 720 mm 1,057 mm 2,165 mm
Rainfall in the driest quarter 71 mm 200 mm 329 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 1,981 research-grade observations of Lycopus uniflorus 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 12 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.

  • Euhemus uniflorus (Michx.) Raf.
  • Lycopus communis E.P.Bicknell
  • Lycopus coreanus H.Lév.
  • Lycopus membranaceus E.P.Bicknell
  • Lycopus parviflorus (Benth.) Maxim.
  • Lycopus pumilus Vahl
  • Lycopus uniflorus f. flagellaris Fernald
  • Lycopus uniflorus var. macrophyllus Farw.
  • Lycopus uniflorus var. membranacea Farw.
  • Lycopus uniflorus var. ovatus Fernald & H.St.John
  • Lycopus uniflorus var. parviflorus (Benth.) Kitag.
  • Lycopus virginicus var. parviflorus Benth.

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.