Equisetum hyemale aka Horsetail

Equisetum hyemale is an evergreen perennial in the horsetail family. Its common names include rough horsetail and scouring rush. It grows wild across much of Eurasia and North America. It is also native to Britain and Ireland. Wild plants grow in wet woods and on moist slopes. They also grow beside streams, lakes, rivers, and ponds. Its upright stems give it a rush-like form.

Garden plants stand around 3–6 feet (0.9–1.8 metres) tall. RHS lists a height range reaching 8.2 feet (2.5 metres). Reported spreads range from 1.6–6 feet (0.5–1.83 metres). The dark green stems are stiff, rough, hollow, and ridged. Their joints give them a bamboo-like look. Tiny leaves clasp each joint and form a gray sheath. Black bands mark the stems at these joints. This plant does not flower. Its green stems, rather than blooms, provide its main garden interest.

Grow it in full sun or part shade. It tolerates deep shade and a wide range of soils. Clay, loam, and sand can all support growth. It accepts acid, neutral, and alkaline soil. Keep the soil moist, with wet ground also suitable. Plants can grow in water about 4 inches (0.1 metres) deep. RHS recommends fertile soil that stays moist throughout the year. Sources place it in USDA zones 4–9 and RHS H7. Divide plants in spring to make new plants. Remove dead or damaged stems to keep the clump neat.

Use it beside ponds, in bog gardens, or in wet hollows. Its upright stems also suit Japanese gardens and large patio pots. Chicago Botanic Garden lists it as deer resistant. Pests and diseases seldom cause serious trouble. Its spread presents a much greater problem. Branched rhizomes run far and deep beneath the soil. Small pieces left behind can grow into new plants. Soil barriers or containers can help limit this spread. Established colonies can be very hard to remove.

The silica-rich stems have served as scourers and polishing tools. Other recorded uses include pink dye and hollow-stem whistles. PFAF reports food uses for cooked young shoots and rhizomes. Their coarse texture limits their value as food. Large amounts can be toxic because the plant contains thiaminase. This enzyme can deplete the body's supply of B vitamins. Heat or thorough drying destroys the enzyme. PFAF also records medicinal uses, but these do not establish safe self-treatment.