Equisetum pratense aka Meadow Horsetail

Equisetum pratense is a perennial known as meadow horsetail or shady horsetail. It belongs to the horsetail family, Equisetaceae. Its native range spans the subarctic and temperate Northern Hemisphere. Records cover much of Europe, northern Asia, and North America. The RHS lists it as native to Britain and Ireland. In the wild, it grows along grassy stream banks. Habitat records reach about 2,950 feet [900 metres] above sea level.

This plant reaches about 2 feet [0.6 metres] in height. It grows from rhizomes and has a deep root system. Those roots can spread far into the soil. A well-placed plant can spread freely without help from the gardener. This makes its spread worth considering before planting in beds. The source lists both cultivated beds and bog gardens as possible settings. Its need for moist soil suits these damp planting sites.

Grow meadow horsetail in sun or light shade. It accepts sandy soil, loam, and heavy clay. It also tolerates mildly acid, neutral, and mildly alkaline ground. The stated preferred pH range is 6.5 to 7.5. Keep the soil moist rather than choosing a dry site. PFAF lists USDA hardiness zones 4–8 for this species. It also reports cold tolerance near −22°F [−30°C]. These figures describe a plant suited to cold temperate gardens.

Control of its roots is a key part of cultivation. PFAF warns that the plant can become invasive in gardens. It recommends a large container sunk into the ground. This keeps the spreading root system within a set space. Division offers one way to raise more plants. Growing it from spores is much harder, according to PFAF. Collect ripe spores in spring and sow them at once. Use sterile compost, sow on the surface, and keep it moist.

Records describe roots as food, either raw or cooked. They also mention past use of peeled stems, bases, and tubers. These records do not establish that eating the plant is safe. PFAF warns that large amounts can cause serious health problems. The plant contains thiaminase, an enzyme that reduces available vitamin B. Heat or thorough drying destroys that enzyme. The source also notes equisetic acid as a further concern. Treat the food records with caution rather than as serving advice.