Dryopteris sieboldii

Dryopteris sieboldii is known as Siebold's wood fern or Asian wood fern. This evergreen perennial comes from China and Japan. Some sources also include Taiwan in its range. It grows on forest floors, including dry sites in mountain woods. Its name honours Philipp Franz Balthasar von Siebold, a physician and botanist.

This slow-growing fern forms clumps from short rhizomes that creep. Garden plants reach about 1–3.3 feet (0.3–1 metre) tall. They spread about 2–3.3 feet (0.6–1 metre) wide. Plants may take five to ten years to reach full size. The broad fronds have a tough, leathery feel. Their green colour can have a blue tint. Each frond has just two to five pairs of undivided pinnae. The end pinna measures about 0.7–1 foot (0.2–0.3 metre) long. Sterile fronds arch out, while fertile fronds stand more upright. Fertile fronds also have slightly narrower pinnae. The plant has no flowers or fruit; it spreads by spores.

Grow this fern in partial or full shade, with shelter. It needs soil rich in humus that holds moisture but drains well. Clay and loam suit it. NC State lists acid soil, while RHS also accepts neutral and alkaline soils. Established plants can cope with some drought and heat. This tolerance does not replace their preference for moist soil. NC State lists USDA zones 6b–9b; RHS rates it H6. The fronds stay green down to about 5°F. In colder conditions, the plant may be semi-evergreen.

Its broad leaves make a useful accent in a shaded bed. It suits woodland, Asian-style and winter gardens, as well as small spaces. It also grows in pots and beneath shrubs or roses. Plant it alone as an accent or in small groups. Deer seldom damage it, and it tolerates deep shade. RHS reports few pest or disease problems. Care is light: remove dead or damaged fronds when needed. Divide plants in spring or autumn, or raise them from spores.

Plants For A Future records dried, powdered roots as an edible use. It gives the plant a low food-use rating and urges caution. Its hazard note states that fresh plants contain thiaminase. This enzyme can deplete vitamin B when eaten in large amounts. Heat or thorough drying destroys the enzyme. The source also warns about broader fern risks, without species-specific reports of carcinogens. These notes do not establish that this fern is safe to eat. No medicinal uses are recorded by that source.