Sweet Colt's-foot (Petasites sagittatus)

Life history

Species overview

Sweet Colt's-foot (Petasites sagittatus), a Wisconsin Threatened plant, is found in cold marshes and swamp openings, often forming large clones. Blooming occurs throughout May; fruiting occurs throughout June. The optimal identification period for this species is late May through late August.

Synonyms: Petasites dentatus, P. frigidus var. sagittatus, Tussilago sagittata

Identification

• Distinguishing characteristics: Distinguished by combination of white flowers and toothed (vs. lobed) basal leaves.
• Flower characteristics: Inflorescence in a raceme or corymb-shape; whitish flowers, the outer 10 to 25 in pistillate heads; rays commonly 8 to 9 mm.
• Fruit characteristics: Cypselae (achene surrounded by calyx sheath) 3 to 3.5 mm long, ribbed.
• Leaf characteristics: Basal leaves triangular-ovate, cordate or more commonly arrow-shaped and downward-pointing at the base, to 30 cm, pinnipalmately veined, with 20 to 45 teeth on each side, densely white-hairy beneath.

Phenology

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

Other

• Growth form: Forb-erect
• Vegetative reproduction: Rhizomatous
• Life cycle: Perennial
• Comments: Associated Species: Calamagrostis canadensis, Salix petiolaris, Alnus rugosa, Cornus stolonifera, Carex stricta, Sparganium glomeratum.This species hybridizes with Petasites palmatus.

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 Sweet Colt's-foot (Petasites sagittatus). 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.

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 cold marshes and swamp openings, often forming large clones.
• Soils: Wet soils.

Natural communities

This table lists the natural communities that are associated with Sweet Colt's-foot. 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 Sweet Colt's-foot. The scores (3=High, 2=Moderate, 1=Low, 0=None) also correspond to the map.

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 locating landings, staging areas, or access routes on or near known populations.

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.
• Follow BMPs, especially around streams and use care near ravines, steep slopes, cliffs, rock outcrops, etc.

Other resources

Links to additional Sweet Colt's-foot information

• Michigan Natural Features Inventory [PDF exit DNR]

Other links related to vascular plants (all exit the DNR website)

• Wisconsin Flora
• NatureServe Explorer
• Atlas of Wisconsin Prairie and Savanna Flora - Wisconsin State Herbarium
• USDA - NRCS Plants Database
• USGS Midwestern Wetland Flora - field office guide to plant species
• eFloras
• Cofrin Center for Biodiversity Herbarium
• Intermountain Herbarium Grasses of North America
• Orchids of Wisconsin

Photos

Click to view a larger version. Please considering donating a photo to the Natural Heritage Conservation Program for educational uses. Photo use