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Large Toothwort (Cardamine maxima)

Life history

Species overview

Large Toothwort (Cardamine maxima), a Wisconsin Special Concern plant, is found in rich mesic floodplain terraces. Blooming occurs late April through early June; fruiting occurs throughout June. The optimal identification period for this species is late April through late May.

Synonyms: Cardamine X maxima, Dentaria maxima


  • Distinguishing characteristics: Purple 4-parted flowers; 3 distinctly alternate leaves with 3-parted with ovate leaflets, the margins toothed and distinctly ciliolate. In contrast, C. diphyllya has white flowers and 2 opposite, 3-parted leaves with margins glabrous to merely scabrous.
  • Flower characteristics: Four-parted, purplish, bell-shaped flowers with 11 to 17 mm long petals; peduncle often sparsely pubescent.
  • Fruit characteristics: Elongated, thin pods 2 to 4 cm long.
  • Leaf characteristics: Alternate, distinctly 3, each leaf divided into 3 leaflets; leaflet margins toothed and distinctly ciliolate.


  • Blooming phenology: late April through early June
  • Fruiting phenology: throughout June
  • Optimum time to identify: The optimal identification period for this species is late April through late May


  • Growth form: Forb-erect
  • Vegetative reproduction: Rhizomatous
  • Life cycle: Annual/perennial
  • Comments: Associated Species: Acer saccharum, Tilia americana, Claytonia virginica, Erythronium spp., Cardamine concatenata, C. laciniata.

State status

Status and Natural Heritage Inventory documented occurrences in Wisconsin

The table below provides information about the protected status - state and federal - and the rank (S and G Ranks) for Large Toothwort (Cardamine maxima). See the Working List Key for more information about abbreviations. Counties shaded blue have documented occurrences for this species in the Wisconsin Natural Heritage Inventory database. The map is provided as a general reference of where this species has been found to date and is not meant as a range map.

Documented locations of Cardamine maxima in the Natural Heritage Inventory Database as of July 2015.

Summary Information
State StatusSC
Federal Status in Wisconsinnone
State RankS1
Global RankG5
Tracked by NHIY

Habitats and landscapes

The Natural Heritage Inventory has developed scores indicating the degree to which each of Wisconsin's rare plant species is associated with a particular natural community or ecological landscape. This information is similar to that found in the Wildlife Action Plan for animals. As this is a work in progress, we welcome your suggestions and feedback.

General habitat information

  • Habitat description: Found in rich mesic floodplain terraces.
  • Soils: Rich, mesic soils.

Natural communities

This table lists the natural communities that are associated with Large Toothwort. Scores for natural community associations are: "significant" association (score=3), "moderate association" (score=2) or the species can be present but is only weakly associated with the community (score=1).

Natural communities score
Mesic Floodplain Terrace 3

Ecological landscapes

This table lists the ecological landscape association scores for Large Toothwort. The scores (3=High, 2=Moderate, 1=Low, 0=None) also correspond to the map.

Map of the Ecological Landscapes of Wisconsin.

Ecological landscape score
Forest Transition 1
Superior Coastal Plain 3

Species guidance

The Endangered Resources Program has developed avoidance measures and management guidelines for plants on the Natural Heritage Working List. These are a work in progress, and we welcome your suggestions and feedback. Sources used in developing this information can be found here.

Avoidance measures

These are specific actions designed to avoid "take" (mortality) of this species.

  • Avoid broadcast spraying of herbicides; use care with spot spraying.
  • Avoid known individual plant locations and conduct operations elsewhere when they are least likely to cause damage. Ideally, this would involve frozen, snow-covered ground. However, in areas of the state where frozen conditions are unreliable, very dry soils late in the growing season might be the best available alternative. Consult with a biologist, if needed.
  • Avoid site preparation that heavily disturbs herbaceous ground layer and soil; these include bulldozing and furrowing, as well as grubbing and stump removal.

Management guidance

Management guidelines are additional considerations that may help maintain or enhance habitat for this species

  • Minimize disturbance to hydrology, including soil disturbance from rutting.
  • Avoid rapid and dramatic reductions in canopy cover or basal area in wet areas to reduce risk of swamping.


Large Toothwort Photo.

The rhizome of C. maxima has conspicuous constrictions along its length.

Photo by Kevin Doyle, Wisconsin DNR.

Large Toothwort Photo.

Photo by Kevin Doyle, Wisconsin DNR.

Large Toothwort Photo.

The leaves of C. maxima are alternate whereas the similar C. diphylla are opposite.

Photo by Kevin Doyle, Wisconsin DNR.

Large Toothwort Photo.

Photo © Robert Bierman, Wisconsin State Herbarium

Support for Wisconsin's rare plant information has been provided by the Division of Forestry, the Endangered Resources Fund and the Wisconsin Rare Plant Preservation Fund. To donate, visit the Natural Resources Foundation of Wisconsin [exit DNR].

Last revised: Wednesday, May 05, 2021
Southwest Savanna Southern Lake Michigan Coastal Western Coulees and Ridges Southeast Glacial Plains Central Sand Hills Central Lake Michigan Coastal Central Sand Plains Northern Lake Michigan Coastal Northern Lake Michigan Coastal Northeast Sands Western Prairie North Central Forest Northern Highlands Northwest Lowlands Northwest Sands Northwest Lowlands Superior Coastal Plains Forest Transition