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Kevin Doyle

Snow Trillium (Trillium nivale)

Life history

Species overview

Snow Trillium (Trillium nivale), a State Threatened plant, is found in hardwood forests, sometimes second-growth, often adjacent to rivers or streams. Blooming occurs late March through late April; fruiting occurs throughout April. The optimal identification period for this species is late March through late April.

Synonyms: None


  • Distinguishing characteristics: Leaves and petals obtuse to subacute.
  • Flower characteristics: Petals white, sometimes pinkish at the base, elliptic, 2.5 to 4 cm; sepals lanceolate and much shorter than petals; anthers 7 to 10 mm.
  • Fruit characteristics: Ovary roundly 3-lobed.
  • Leaf characteristics: Whorled, individual leaves elliptic to ovate, 3 to 5 cm, rounded at the base; petiole 5 to 10 mm.


  • Blooming phenology: late March through late April
  • Fruiting phenology: throughout April
  • Optimum time to identify: late March through late April


  • Growth form: Forb-erect
  • Vegetative reproduction:
  • Life cycle: Perennial
  • Comments: Associated Species: Acer saccharum, Tilia americana, Fagus grandifolia, Quercus rubra, Jeffersonia diphylla, Hydrastis canadensis, Anemonella thalictroides, Enemion biternatum

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 Snow Trillium (Trillium nivale). 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 Trillium nivale in the Natural Heritage Inventory Database as of July 2015.

Summary Information
State StatusTHR
Federal Status in Wisconsinnone
State RankS3
Global RankG4
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 hardwood forests, sometimes second-growth, often adjacent to rivers or streams.
  • Soils: Rich, moist soils.

Natural communities

This table lists the natural communities that are associated with Snow Trillium. 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).

Ecological landscapes

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

Map of the Ecological Landscapes of Wisconsin.

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 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 broadcast spraying of herbicides; use care with spot spraying.

Management guidance

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

  • Maintain high forest canopy cover; this species requires shaded habitat conditions.
  • Follow BMPs, especially around streams and use care near ravines, steep slopes, cliffs, rock outcrops, etc.
  • Survey for and control invasive plants prior to conducting timber operations, as these can be spread by vehicles and often respond vigorously to increased light; see forestry BMPs for invasive species.


Snow Trillium  Photo.

Snow trillium (Trillium nivale) growing near the Lower Wisconsin river in Grant Co.

Photo by Ryan O'Connor, Wisconsin DNR.

Snow Trillium  Photo.

The snow trillium (WI Threatened) occurs in rich mesic hardwood forests.

Photo by Armund Bartz, Wisconsin DNR.

Snow Trillium  Photo.

Photo by W.A. Smith, Wisconsin DNR.

Snow Trillium  Photo.

Photo by Thomas Meyer, Wisconsin DNR.

Snow Trillium  Photo.

Photo by Thomas Meyer, Wisconsin DNR.

Snow Trillium  Photo.

Photo by W.A. Smith, Wisconsin DNR.

Snow Trillium  Photo.

Photo by  staff, Wisconsin DNR.

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: Thursday, September 24, 2015
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