Athyrium yokoscense
Family: Dryopteridaceae
What it is like
Athyrium yokoscense is a FERN growing to 0.3 m (1ft). See above for USDA hardiness. It is hardy to UK zone 7. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils, prefers well-drained soil and can grow in heavy clay soil. Suitable pH: mildly acid, neutral and basic (mildly alkaline) 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.
Height (m): 0.3
Where it is found
Woods in lowland and mountains all over Japan. Thin deciduous woods and thickets.
E. Asia - China, Japan, Korea.
Conservation Status:
Countries/locations it is found in
How it is used
Food
Rating: 1
Very young fronds (croziers) - boiled. Some caution is advised. See the notes above on toxicity.
Medicine
Rating: 0
Other
Rating:
How it is grown
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.
Propagating it: 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.
Best place to grow: Woodland Garden Dappled Shade; Shady Edge; not Deep Shade; Bog Garden;
Habit: Fern
Hardiness: 6-9
Growth:
Soil: Light (sandy), medium, heavy (clay)
Shade: Full shade, semi-shade
Moisture: Moist, wet
Things to keep in mind
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.