Equisetum telmateia aka Great Horsetail

Equisetum telmateia is also known as great horsetail. It is part of the Equisetaceae family. Its native range takes in Macaronesia and Europe. It also spans northwestern Africa and Iran. It grows wild across Britain and Ireland. This plant lives for years but sheds its leaves. Deep stems called rhizomes keep it alive below ground. It likes damp, shaded banks, woods and sites like these. The RHS calls it Britain's largest native horsetail.

Its upright stems grow over 3.3 feet [1 metre] tall. They look pale green-white, with black rings at each joint. Each whorl, or ring, holds 20–40 fine green branches. These grow about 0.7 feet [0.2 metres] long. The many branches give the plant a bushy shape. Black rhizomes spread far below ground and last for years. These stems cause most of the plant's spread.

Great horsetail has no flowers. It makes spores in oval cones in early spring. Shorter stems, apart from the leafy stems, bear these cones. These fertile stems look brown and white. Spores give the plant one way to form new plants. But stems below ground cause most spread in gardens. The leaves die back, rather than stay green all year.

The RHS lists full sun, part shade and full shade. The plant accepts chalk, clay, loam and sandy soils. It grows in acid, neutral and alkaline soils. Moist soil suits the sites where it grows wild. The RHS also lists a wide range of drainage conditions. Its H7 rating shows it can cope with harsh cold in continental Europe. Plants For A Future gives USDA zones 5–9. The RHS gives five to ten years to reach full size.

Its bold shape can suit garden areas that get less care. Wood edges and shaded beds may also suit it. But its deep rhizomes make rooted plants hard to remove. The RHS says it does not compete hard with other plants. It needs no pruning. Pests and disease tend to leave it alone. People have used its silica-rich stems to scour and polish. Other uses on record include basket work and liquid feed. Plant sprays are another use.

Plants For A Future lists food uses for shoots and roots. These include spring fertile shoots and very young leafy shoots. It also lists cooked roots, but rates edibility low. Large amounts can cause grave harm due to thiaminase. This enzyme can drain the body's store of B vitamins. Heat or thorough drying breaks down the enzyme. This does not mean it is safe to eat without limits. Past uses as medicine include poultices, or packs placed on skin. They also include mixtures that help the body pass urine.