Zenmai

Osmunda japonica

Physical Characteristics

Osmunda japonica is a FERN growing to 1 m (3ft 3in). See above for USDA hardiness. It is hardy to UK zone 6. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils and can grow in very acid soils. It can grow in semi-shade (light woodland) or no shade. It prefers moist or wet soil.

Distribution

E. Asia - China, Japan.

Habitats

Woodland Garden Dappled Shade; Shady Edge; Bog Garden;

Edible Uses

Edible Parts: Leaves Root Edible Uses: Young fronds - cooked[105, 177]. An edible starch is obtained from the rhizome[105, 177].

Medicinal Uses

None known

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].