Sensitive Fern

Onoclea sensibilis

Physical Characteristics

Onoclea sensibilis is a deciduous Fern growing to 0.5 m (1ft 8in) by 0.5 m (1ft 8in) at a fast rate. See above for USDA hardiness. It is hardy to UK zone 4 and is not frost tender. The seeds ripen from June to October. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils. Suitable pH: mildly acid and neutral soils and can grow in very acid soils. It can grow in full shade (deep woodland) or semi-shade (light woodland). It prefers moist or wet soil.

Distribution

N. America - east of the Rockies to N.E. Asia.

Habitats

Woodland Garden Dappled Shade; Shady Edge; not Deep Shade; Ground Cover; Bog Garden;

Edible Uses

Edible Parts: Leaves Root Shoots Edible Uses: The young uncurled leaves, often called 'fiddleheads', are used as a vegetable or eaten raw[[159, 177, 183]. Remove the brown scales and then steam the leaves in very little water[213]. The young shoots have been sold as delicacies in Asian markets[213]. Root - cooked[105, 161, 177, 183]. A famine food, it is only used in times of scarcity[213].

Medicinal Uses

Galactogogue Poultice Women's complaints Sensitive fern has not been much used medicinally. However, one native North American Indian tribe did employ it quite widely to treat various women's complaints[257]. An infusion of the root has been used to treat the pain following childbirth[257]. A decoction of the roots has been used to treat fertility in women, to give strength after childbirth, to start the menses, and to treat swellings, cramps and a sore abdomen[257]. An infusion of the whole plant, or just the root, has been applied externally to full breasts where the milk will not flow[257]. A poultice of the plant is used in treating deep cuts[257].

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].