Common Name:

General Information

Athyrium yokoscense is a deciduous ferm forming a clump of fronds 40 - 60cm tall from a short, stout, erect rhizome[].
The plant is sometimes harvested from the wild for local use as a food. It is sometimes grown in gardens as an ornamental.

Known Hazards

Although we have found no reports of toxicity for this species, a number of ferns contain carcinogens so some caution is advisable[].
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[].

Botanical References

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Range

E. Asia - Russian Far East (Primorye), China, Japan, Korea.

Habitat

Woods in lowland and mountains all over Japan[]. Thin deciduous woods and thickets[]. Rock crevices in forests; at elevations from 100 - 2,400 metres[].

Properties

Edibility Rating
Habit	Deciduous Fern
Height	0.50 m
Cultivation Status	Ornamental, Wild

Cultivation Details

An easily grown plant, it is calcifuge and prefers an acid soil with a pH from 4.5 to 6.5, but it tolerates alkaline soils if plenty of leaf mould is added[]. Grows well in heavy clay soils. Prefers a moist sheltered site with moderately high atmospheric humidity[]. Succeeds in a semi-shaded bog-garden or in damp woodland, also in garden borders in full or part shade[].
This species is very variable, partly according to altitudes and habitats[]. Plants growing on sunny rocks and in high mountains look like Athyrium rupestre and may be distinguished as var. alpicola[]. Lowland plants with deeply tripinnatifid leaves may be called var. dilatatum[].
Members of this genus are rarely if ever troubled by browsing deer[].

Edible Uses

Very young fronds (croziers) - boiled[]. Some caution is advised. See the notes above on toxicity.

Medicinal

None known

Other Uses

None known

Propagation

Spores - surface sow in a pot of sterile compost in a shady part of the greenhouse and keep moist, this is most easily done by putting the pot in a plastic bag. Pot up small clumps of the plants when they are large enough to handle and keep them moist until they are established. Plant out in late spring of the following year.
Division in spring as plants come into growth. Larger divisions can be planted straight into their permanent positions whilst smaller clumps are best potted up and kept in a cold frame until they are growing away well.