Synonyms : Equisetum maximum. auct.
Common Names : Great horsetail or Northern giant horsetail
Habitat : Equisetum telmateia is native to Europe, including Britain, from Sweden south and east to N. Africa and W. Asia, N.W. N. America. It grows on damp shady banks etc, to 350 metres.
Equisetum telmateia is a herbaceous perennial plant, with separate green photosynthetic sterile stems, and pale yellowish non-photosynthetic spore-bearing fertile stems. The sterile stems, produced in late spring and dying down in late autumn, are 30–150 cm (rarely to 240 cm) tall (the tallest species of horsetail outside of tropical regions) and 1 cm diameter, heavily branched, with whorls of 14–40 branches, these up to 20 cm long, 1–2 mm diameter and unbranched, emerging from the axils of a ring of bracts. The fertile stems are produced in early spring before the sterile shoots, growing to 15–45 cm tall with an apical spore-bearing strobilus 4–10 cm long and 1–2 cm broad, and no side branches; the spores disperse in mid spring, with the fertile stems dying immediately after spore release. It also spreads by means of rhizomes that have been observed to penetrate 4 meters into wet clay soil, spreading laterally in multiple layers. Occasional plants produce stems that are both fertile and photosynthetic. It is hardy to zone (UK) 6. It is in flower in March, and the seeds ripen in April.
There are two subspecies:
*Equisetum telmateia subsp. telmateia. Great Horsetail. Europe, western Asia, northwest Africa. Main stem between branch whorls pale greenish white.
*Equisetum telmateia subsp. braunii (Milde) Hauke. Northern Giant Horsetail. Western North America, from southeastern Alaska and western British Columbia south to California. Main stem between branch whorls green.
Prefers a moist soil with a pH between 6.5 and 7.5. Plants are hardy to about -30°c. Plants have a deep and penetrating root system and can be invasive. If grown in the garden they are best kept in bounds by planting them in a large container which can be sunk into the ground.
Spores – best collected as soon as they are ripe in the spring and surface-sown immediately on a sterile compost. Keep moist and pot up as soon as the plants are large enough to handle. Very difficult. Division. The plants usually spread very freely when well sited and should not really need any assistance.
Strobil (the fertile shoots in spring) – raw or cooked. The tough outer fibres are peeled off, or can be chewed and then discarded. The vegetative shoots, produced from late spring onwards, were occasionally cleaned of their leaves, sheathing and branches and then eaten by native North American Indians, but only when very young and tightly compacted. Root – cooked.
Astringent; Diuretic; Poultice.
The plant is astringent and diuretic. A decoction has been used to treat ‘stoppage of urine’. A poultice of the rough leaves and stems is applied to cuts and sores.
Basketry; Fungicide; Hair; Liquid feed; Polish; Sandpaper.
The stems are very rich in silica. They are used for scouring and polishing metal and as a fine sandpaper. The stems are first bleached by repeated wetting and drying in the sun. They can also be used as a polish for wooden floors and furniture. The infused stem is an effective fungicide against mildew, mint rust and blackspot on roses. It also makes a good liquid feed. Used as a hair rinse it can eliminate fleas, lice and mites. The black roots have been used for imbrication on coiled baskets.
Known Hazards : Large quantities of the plant can be toxic. This is because it contains the enzyme thiaminase, a substance that can rob the body of the vitamin B complex. In small quantities this enzyme will do no harm to people eating an adequate diet that is rich in vitamin B, though large quantities can cause severe health problems. The enzyme is destroyed by heat or thorough drying, so cooking the plant will remove the thiaminase. The plant also contains equisetic acid – see the notes on medicinal uses for more information.
Disclaimer : The information presented herein is intended for educational purposes only. Individual results may vary, and before using any supplement, it is always advisable to consult with your own health care provider.