Practical
Plants

Dryopteris crassirhizoma

Crown Wood-Fern

No photo available

Taxonomy and growth

Height
1 m

Uses

Toxicity

Toxicity warning. The historical record reports a hazard for this plant. Do not use it to decide which parts are safe to eat or use medicinally.

Although we have found no reports for this species, a number of ferns contain carcinogens so some caution is advisable[6]. The fresh plant contains 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[1]. However, there have been reports for other species of ferns suggesting that even cooked fronds can have a long term harmful effect. Some caution is therefore advised.

Edible uses

Young fronds[4]. No further details, but we would advise caution. See the notes above on toxicity.

Plant part
Leaves

Medicinal uses

Historical medicinal uses. These records describe reported uses. They do not establish safety or effectiveness. Ask a qualified health professional before using any plant medicinally.

The root stalks are analgesic, antibacterial, anti-inflammatory, antiviral, astringent, febrifuge, haemostatic, vermifuge and vulnerary[9][11]. A decoction of the dried root is depurative and resolvent[7]. The root contains 'filicin', a substance that paralyses tapeworms and other internal parasites and has been used as a worm expellent for humans and also in veterinary medicine[7][9]. It is one of the most effective treatments known for tapeworms - its use should be immediately followed by a non-oily purgative such as magnesium sulphate in order to expel the worms from the body[9]. An oily purge, such as caster oil, increases the absorption of the fern root and can be dangerous[9]. The root is also taken internally in the treatment of internal haemorrhage, uterine bleeding, mumps and feverish illnesses[9]. The root is harvested in the autumn and can be dried for later use, it should not be stored for longer than 12 months[9]. This remedy should be used with caution and only under the supervision of a qualified practitioner[9]. The root is toxic and the dosage is critical[9]. See also the notes above on toxicity. Externally, the root is used in the treatment of abscesses, boils, carbuncles and sores[9].

Product or use
Analgesic
Product or use
Depurative
Product or use
Haemostatic
Product or use
Resolvent
Product or use
Vermifuge

Environment

Range
E. Asia - Japan, Korea, Manchuria.
Habitat
Mountains all over Japan[2]. A terrestrial fern, growing on the humus-rich floor of temperate forests, often in colonies[10].
Shade tolerance
partial shade
Water
moderate
Hardiness
Zone 6+
Soil textures
sandy, loamy, clay
Soil pH
acid, neutral
Tolerances
drought
Tolerates Nutritionally Poor Soil
No
Drought
tolerant

Propagation

Spores - can be sown at any time of the year in a greenhouse. Surface sow on a sterilised compost and keep moist, possibly by placing the pot in a plastic bag. Germinates in 1 - 3 months at 20°c. Pot up small clumps of the plants when they are large enough to handle and grow on in a shady part of the greenhouse until large enough to plant out. Division in spring. Larger clumps can be replanted direct into their permanent positions, though it is best to pot up smaller clumps and grow them on in a cold frame until they are rooting well. Plant them out in the spring.

Cultivation

Prefers an acid to neutral soil, succeeding in ordinary fertile soil in a shady position[3][6]. Prefers a moist soil[5], but is drought tolerant when well established[6]. Members of this genus are rarely if ever troubled by browsing deer[8].

References

  1. Schofield. J. J. Discovering Wild Plants - Alaska, W. Canada and the Northwest.

    ↩

  2. Kariyone. T. Atlas of Medicinal Plants.

    ↩

  3. Bird. R. (Editor) Focus on Plants. Volume 5. (formerly 'Growing from seed') Thompson and Morgan. 1991-00-00

    ↩

  4. Kunkel. G. Plants for Human Consumption. Koeltz Scientific Books 1984-00-00 ISBN 3874292169

    ↩

  5. Brickell. C. The RHS Gardener's Encyclopedia of Plants and Flowers Dorling Kindersley Publishers Ltd. 1990-00-00 ISBN 0-86318-386-7

    ↩

  6. Huxley. A. The New RHS Dictionary of Gardening. 1992. MacMillan Press 1992-00-00 ISBN 0-333-47494-5

    ↩1↩2↩3

  7. Duke. J. A. and Ayensu. E. S. Medicinal Plants of China Reference Publications, Inc. 1985-00-00 ISBN 0-917256-20-4

    ↩1↩2

  8. Thomas. G. S. Perennial Garden Plants J. M. Dent & Sons, London. 1990-00-00 ISBN 0 460 86048 8

    ↩

  9. Bown. D. Encyclopaedia of Herbs and their Uses. Dorling Kindersley, London. 1995-00-00 ISBN 0-7513-020-31

    ↩1↩2↩3↩4↩5↩6↩7↩8↩9

  10. Flora of Japan www.foj.info

    ↩

  11. Medicinal Plants in the Republic of Korea World Health Organisation, Manila 1998-00-00 ISBN 92 9061 120 0

    ↩

Edit this page