Equisetum sylvaticum aka Wood Horsetail

Equisetum sylvaticum lives for more than two years. Its names include wood horsetail and wood bottlebrush. It belongs to Equisetaceae, the horsetail family. Its native range spans the subarctic and temperate Northern Hemisphere. This takes in parts of Europe, Asia, and North America. Britain and Ireland also form part of its native range. It grows wild in damp woods, some with acid soils. It also grows on moors.

Plants reach about 2 feet [0.6 metres] tall. Rhizomes are stems that grow below ground. They send out roots and new shoots along their length. These stems let plants spread past the first planting site. The roots grow deep and can be hard to contain. The draft gives no fixed width for a full-grown plant. This is because its spread can go on. You can also raise plants from spores in spring. Plants For A Future says this is hard to do.

This plant suits damp woodland gardens and shaded edges. It grows in part shade and likes soil that stays moist. It can grow in sand, loam, or clay. It copes with mildly acid, neutral, or mildly alkaline soil. Its stated best pH range is 6.5 to 7.5. Plants For A Future reports hardiness to about −22°F [−30°C]. Its spread needs care in a small garden. That source suggests sinking a large pot into the ground. This helps keep the stems below ground within bounds.

Records list uses for this plant beyond the garden. Its stems can scour metal and smooth or polish wood. They also yield a pale pink dye. Plants For A Future records stem infusions against plant diseases caused by fungi. These include mildew, mint rust, and rose blackspot. The source also lists use as liquid feed and mulch. Past uses as medicine include remedies for urinary problems and bleeding. These reports do not prove that such use is safe. Nor do they prove that it helps treat illness.

Records list food uses for cooked roots and cooked spring fertile shoots. The roots supply starch, but the shoots offer little food value. Plants For A Future gives it a low score for food use. Eating large amounts can cause great harm. The plant contains an enzyme called thiaminase. This breaks down vitamin B1. That source says heat or thorough drying destroys the enzyme. This does not mean that use without limits is safe. Read its food uses with these clear warnings about its toxic effects.