Herb: Giant Horsetail

Latin name: Equisetum telmateia

Synonyms: Equisetum maximum

Family: Equisetaceae (Horsetail Family)

Medicinal use of Giant Horsetail:

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.

Description of the plant:


2 m
(6 1/2 foot)


Habitat of the herb:

Damp shady banks etc, to 350 metres.

Edible parts of Giant Horsetail:

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.

Other uses of the herb:

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.

Propagation of Giant Horsetail:

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.

Cultivation of the herb:

Damp shady banks etc, to 350 metres.

Known hazards of Equisetum telmateia:

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.

Plant information taken from the Plants For A Future.