Cardamine pensylvanicaMuhl. ex Willd.

Pennsylvania bittercress

WFO wfo-0000587327 Accepted WFO 2026-06 8 photographs CC0 / CC BY

Plate 1 figs. a–h · 8 separate observations

Cardamine pensylvanica, photographed by Mary E. Macaulay, P.Eng.
fig. a Mary E. Macaulay, P.Eng., CC BY 4.0 / 2022-06-01 / obs. 202569772
Cardamine pensylvanica, photographed by Bruce Cook
fig. b Bruce Cook, CC0 1.0 / obs. 201064164
Cardamine pensylvanica, photographed by Quinten Wiegersma
fig. c Quinten Wiegersma, CC BY 4.0 / obs. 201774871
Cardamine pensylvanica, photographed by Steven Lamonde
fig. d Steven Lamonde, CC BY 4.0 / obs. 199200309
Cardamine pensylvanica, photographed by Steven Lamonde
fig. e Steven Lamonde, CC BY 4.0 / obs. 199200327
Cardamine pensylvanica, photographed by Steven Lamonde
fig. f Steven Lamonde, CC BY 4.0 / obs. 199200585
Cardamine pensylvanica, photographed by Steven Lamonde
fig. g Steven Lamonde, CC BY 4.0 / obs. 199194105
Cardamine pensylvanica, photographed by Steven Lamonde
fig. h Steven Lamonde, CC BY 4.0 / obs. 199194120

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
01264626
Filed as
Cardamine pensylvanica Muhl. ex Willd.
Det. by
D. E. Atha 2015-01-01
Collected
E. P. Bicknell 1894-05-27
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 62 botanical countries

Regions where Cardamine pensylvanica is native: Alabama, Alaska, Alberta, Arkansas, British Columbia, California, Colorado, Connecticut, Delaware, District of Columbia, Florida, Georgia, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Labrador, Louisiana, Maine, Manitoba, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Brunswick, New Hampshire, New Jersey, New Mexico, New York, Newfoundland, North Carolina, North Dakota, Northwest Territories, Nova Scotia, Ohio, Oklahoma, Ontario, Oregon, Pennsylvania, Prince Edward I., Québec, Rhode I., Saskatchewan, South Carolina, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin, Wyoming, Yukon, Bahamas AlabamaAlaskaAlbertaArkansasBritish ColumbiaCaliforniaColoradoConnecticutFloridaGeorgiaIdahoIllinoisIndianaIowaKansasKentuckyLabradorLouisianaMaineManitobaMarylandMassachusettsMichiganMinnesotaMississippiMissouriMontanaNebraskaNevadaNew BrunswickNew HampshireNew JerseyNew MexicoNew YorkNewfoundlandNorth CarolinaNorth DakotaNorthwest TerritoriesNova ScotiaOhioOklahomaOntarioOregonPennsylvaniaPrince Edward I.QuébecSaskatchewanSouth CarolinaTennesseeTexasUtahVermontVirginiaWashingtonWest VirginiaWisconsinWyomingYukon DelawareDistrict of ColumbiaRhode I.Bahamas
Native distribution of Cardamine pensylvanica, 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
Alabama ALA NORTHERN AMERICA
Alaska ASK
Alberta ABT
Arkansas ARK
British Columbia BRC
California CAL
Colorado COL
Connecticut CNT
Delaware DEL
District of Columbia WDC
Florida FLA
Georgia GEO
Idaho IDA
Illinois ILL
Indiana INI
Iowa IOW
Kansas KAN
Kentucky KTY
Labrador LAB
Louisiana LOU
Maine MAI
Manitoba MAN
Maryland MRY
Massachusetts MAS
Michigan MIC
Minnesota MIN
Mississippi MSI
Missouri MSO
Montana MNT
Nebraska NEB
Nevada NEV
New Brunswick NBR
New Hampshire NWH
New Jersey NWJ
New Mexico NWM
New York NWY
Newfoundland NFL
North Carolina NCA
North Dakota NDA
Northwest Territories NWT
Nova Scotia NSC
Ohio OHI
Oklahoma OKL
Ontario ONT
Oregon ORE
Pennsylvania PEN
Prince Edward I. PEI
Québec QUE
Rhode I. RHO
Saskatchewan SAS
South Carolina SCA
Tennessee TEN
Texas TEX
Utah UTA
Vermont VER
Virginia VRG
Washington WAS
West Virginia WVA
Wisconsin WIS
Wyoming WYO
Yukon YUK
Bahamas BAH SOUTHERN AMERICA

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 324 in flower of 457 examined

Peak flowering in Aug. Each bar is the share of Cardamine pensylvanica 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. 324 of 457 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. 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 2,017 observations

Condition 5th percentile Median 95th percentile
Coldest month, mean daily low -15.0 °C -8.1 °C 0.4 °C
Warmest month, mean daily high 21.7 °C 26.5 °C 31.2 °C
Annual rainfall 807 mm 1,216 mm 1,546 mm
Rainfall in the driest quarter 80 mm 246 mm 323 mm

It is found where winters bring hard frost. This is not care advice and it is not a forecast. It is a measurement: we sampled the climate at every one of the 2,017 research-grade observations of Cardamine pensylvanica 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 13 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.

  • Cardamine breweri var. oregana (Piper) Detling
  • Cardamine flexuosa f. grandiflora O.E.Schulz
  • Cardamine flexuosa subsp. pensylvanica (Muhl. ex Willd.) O.E.Schulz
  • Cardamine flexuosa var. gracilis O.E.Schulz
  • Cardamine hirsuta f. pensylvanica (Muhl. ex Willd.) E.L.Rand & Redfield
  • Cardamine hirsuta var. acuminata Nutt.
  • Cardamine hirsuta var. pensylvanica (Muhl. ex Willd.) P.W.Graff
  • Cardamine multifolia Rydb.
  • Cardamine oregana Piper
  • Cardamine pensylvanica var. brittoniana Farw.
  • Cardamine pensylvanica var. pensylvanica
  • Cardamine reflexa Raf.
  • Dracamine pennsylvanica (Muhl. ex Willd.) 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.