Hart's Tongue Fern

Asplenium scolopendrium

Physical Characteristics

Asplenium scolopendrium is an evergreen Fern growing to 0.6 m (2ft) by 0.5 m (1ft 8in) at a slow rate. See above for USDA hardiness. It is hardy to UK zone 5 and is not frost tender. It is in leaf all year, and the seeds ripen from July to August. Suitable for: light (sandy) and medium (loamy) soils and can grow in heavy clay soil. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils and can grow in very alkaline soils. It can grow in full shade (deep woodland) or semi-shade (light woodland). It prefers dry or moist soil.

Distribution

Central and southern Europe, including Britain, to N. Africa and eastwards to Japan.

Habitats

Woodland Garden Dappled Shade; Shady Edge; Ground Cover; North Wall. In. East Wall. In. West Wall. In.

Edible Uses

None known

Medicinal Uses

Astringent Cholagogue Diaphoretic Diuretic Dysentery Expectorant Vulnerary The fronds are astringent, cholagogue, diaphoretic, diuretic, expectorant, vulnerary[4, 7, 9, 165]. Externally it is used as an ointment in the treatment of piles, burns and scalds[4]. An infusion is taken internally for the treatment of diarrhoea, dysentery, gravelly deposits of the bladder and for removing obstructions of the liver and spleen[4]. The fronds are harvested during the summer and can be dried for later use[7].

Known Hazards

Although we have found no reports of toxicity for this species, a number of ferns contain carcinogens so some caution is advisable[200]. Many ferns also contain thiaminase, an enzyme that robs the body of its 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[172].