Petasites frigidus

Common Names

Arctic Sweet Coltsfoot, Arctic Butterbur, Sweet Coltsfoot, Alpine Butterbur, Western Coltsfoot, Arrowhead Sweet Coltsfoot, Arrowleaf Coltsfoot

Summary

Petasites frigidus is a rhizomatous perennial herb native to subarctic and boreal regions of North America and Eurasia. It forms very large mat-like stands via long-branched creeping rhizomes and typically reaches 4 to 20 inches in height, thriving in moist meadows, swamps, streambanks, and other wet areas. Basal leaves are large and highly variable in shape, often reniform or palmately lobed, with upper surfaces densely tomentose and undersides densely white-tomentose. Early-season shoots are pinkish and erect, while later-season shoots are at ground level with fewer leaves. Inflorescences are heads arranged in racemes with a two-type flower system, and flowers are white; the plant is functionally dioecious, with male stems withering after flowering and female stems persisting to fruiting. Reproduction occurs by seeds and vegetatively via rhizomes, forming large clones.

In cultivation, the plant prefers moist or wet soil and can tolerate full sun to shade, but is notably invasive when cultivated and may be too rampant for most gardens outside wild settings. Division is an easy propagation method, with seed propagation information limited. Uses include ground cover in wet, shady plantings; edible leaves can be eaten raw or cooked as a potherb, or used as food and flavoring, and roots and stems can be cooked. Leaves have been used in poultices and infusion of dried leaves used for colds and chest congestion; seed heads have been used as mattress stuffing, and ethnobotany notes indicate medicinal and culinary applications by Pacific Northwest tribes.

Lifecycle

Perennial

Height

4-24 inches

Spread

4-23.5 inches

Hardiness Zones

Zones 6-10

Sunlight Requirements

Ideally Full Sun; tolerates Partial Sun and Partial Shade.

Soil Type

Moist, wet soils

Soil Drainage

Moist but well-drained

Soil pH

Mildly acidic to mildly alkaline soils.

Bloom Color

White

Bloom Time

Spring

Foliage Color

Green with a woolly white underside

Leaf Lifecycle

Deciduous

Growth Rate

Fast

Seasons of Interest

Spring and Summer

Propagation Methods

Seeds and Division

Attracts Wildlife

Attracts insect pollinators, including butterflies; no information about bees, hummingbirds, other pollinators, or birds