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Common Name: Swamp Horsetail

General Information

Equisetum fluviatile is a perennial plant that can grow up to 1.20 metres tall.
It is harvested from the wild for local use as a food and medicine

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[].

Botanical References

Range

Arctic and temperate regions of Europe, including Britain, N. America and Asia.

Habitat

Shallow water in lakes, ponds and ditches[].

Properties

Edibility Rating
Medicinal Rating
Habit	Perennial
Height	1.20 m
Cultivation Status	Wild

Cultivation Details

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[].

Edible Uses

Strobil (the fertile shoots in spring) - cooked[, , ]. Used as an asparagus substitute, though it is neither palatable nor nutritious[]. Caution is advised, see the notes above on toxicity.
Roots - cooked[, , ]. The roots contain a nutritious starch[]. Caution is advised, see the notes above on toxicity.

Medicinal

Horsetails have an unusual chemistry compared to most other plants[]. They are rich in silica, contain several alkaloids (including nicotine) and various minerals[]. The plant is styptic[]. The barren stems are used, they are most active when fresh but can also be dried and sometimes the ashes of the plant are used[]. A decoction applied externally will stop the bleeding of wounds and promote healing[].

Other Uses

None known

Propagation

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.