Osmunda japonica is a Fern found in areas such as E. Asia - China, Japan. A member of the Osmundaceae family, Osmunda japonica Thunb is also known by its common name of Zenmai. The Fern can grow to a height of 1 meters and up to meters wide. The preferred habitat of Moist places all over Japan[58, 200]., with LMH soil and SN moisture levels. .

Zenmai is a zone 6 hardy plant that has medicinal uses - the medicinal usage rating of Zenmai is 0(Binary/Image)

Osmunda japonica is a non flowering plant which is pollinated by .

Known hazards of the plant: 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].

The plant has an edibility rating of 2Young fronds - cooked[105, 177]. An edible starch is obtained from the rhizome[105, 177].

Cultivation tips: Likes a soil of swamp mud and loamy or fibrous peat, sand and loam[1]. Succeeds in most moist soils, preferring acid conditions[200]. Requires a constant supply of water, doing well by ponds, streams etc[1]. Plants thrive in full sun so long as there
is no shortage of moisture in the soil and also in shady situations beneath shrubs etc[200]. Plants are hardy to at least -20°c, they are evergreen in warm winter areas but deciduous elsewhere[200]. Members of this genus are rarely if ever troubled by browsing deer[233]. Closely related to O. regalis[1].

. The plant should best be propagated by Spores - they very quickly lose their viability (within 3 days) and are best sown as soon as they are ripe on the surface of a humus-rich sterilized soil in a lightly shaded place in a greenhouse. Keep the compost moist, preferably by putting a plastic bag over the pot. Plants develop very rapidly, pot on small clumps of plantlets as soon as they are large enough to handle and keep humid until they are well established. Do not plant outside until the ferns are at least 2 years old. Cultivars usually come true to type[200]. Division of the rootstock in the dormant season. This is a very strenuous exercise due to the mass of wiry roots[200].

Young fronds - cooked[105, 177]. An edible starch is obtained from the rhizome[105, 177].