Petasites frigidus aka Arctic Butterbur

Petasites frigidus is a low perennial in the daisy family, Asteraceae. The RHS calls it Arctic butterbur and also lists eldin. Its older name is Tussilago frigida. Kew places its native range from subarctic regions to the northwestern United States. It grows in subarctic and subalpine climates. It is not native to Britain or Ireland. In North America, it grows beside streams, in damp woods, and in bogs.

This plant grows from underground rhizomes and spreads fast. Plants For A Future gives a height of about 0.7 feet [0.2 metres]. Its stated spread is about 3.3 feet [1 metre]. The plant has a low, spreading form. Its foliage gives it value as ground cover in wild gardens. The source describes pink flowers, with flowering from April to May. A separate summary gives late winter, so its timing is not fully consistent. Seeds ripen from May to June. Male and female flowers grow on separate plants. Insects pollinate them, and seed production needs plants of both sexes.

Grow it in deep, fertile soil rich in humus. Keep the soil moist, but avoid stagnant conditions. It can also grow in ordinary garden soil. It accepts sandy soil, loam, and clay. It tolerates mildly acid, neutral, and mildly alkaline conditions. Partial shade is preferred, though it also grows in sun or shade. Plants For A Future lists USDA zones 6–10. Division offers a simple way to raise more plants. Larger pieces can go straight into their final growing spots.

This species suits damp woodland gardens, bog gardens, and rough ground. It can grow among coarse grass cut each autumn. Its fast spread can make it hard to contain. Plants For A Future warns that it can overwhelm formal garden spaces. Its cultivation notes describe it as invasive, despite a conflicting weed flag. Traditional uses include filling mattresses with the cotton-like seed heads. People have also folded leaves into fruit containers and temporary funnels.

Plants For A Future records food uses for leaves, stems, flowers, and roots. Young leaves have been eaten raw or cooked. Stalks, flower heads, and roots have been cooked. Burnt leaves have served as a salt substitute. The source lists no known hazards, but this does not prove safety. It also records traditional medicinal uses, not evidence of treatment benefits.