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Polypodium glycyrrhiza - Eaton.

Common Name Licorice Fern
Family Polypodiaceae
USDA hardiness 6-9
Known Hazards 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].
Habitats Rocks, mossy tree trunks, logs etc, below 600 metres in coniferous and mixed forests in California[71]. Cliffs and rocky slopes along coasts, often epiphytic, on a variety of substrates[270].
Range Western N. America - Alaska to California.
Edibility Rating    (1 of 5)
Other Uses    (0 of 5)
Weed Potential No
Medicinal Rating    (2 of 5)
Care (info)
Fully Hardy Moist Soil Semi-shade Full sun
Polypodium glycyrrhiza Licorice Fern

Polypodium glycyrrhiza Licorice Fern


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Physical Characteristics

 icon of manicon of fern
Polypodium glycyrrhiza is a FERN growing to 0.5 m (1ft 8in) by 0.5 m (1ft 8in).
See above for USDA hardiness. It is hardy to UK zone 7. The seeds ripen from November to March.
Suitable for: light (sandy), medium (loamy) and heavy (clay) soils. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It can grow in semi-shade (light woodland) or no shade. It prefers moist soil and can tolerate drought.

UK Hardiness Map US Hardiness Map


Plant Habitats

Woodland Garden Dappled Shade; Shady Edge; North Wall. In. East Wall. In.

Edible Uses

Edible Parts: Root
Edible Uses:

Root - raw or cooked[257] The root is sweetly liquorice-flavoured but is thin and fibrous and virtually inedible[200]. The root was commonly chewed for its very pleasant flavour by many native North American Indian tribes[256, 257]. It was often used as an appetiser, especially for children who would not eat[256]. Apart from its used as a pleasantly flavoured chew, it was seen as a famine food and was only used when there was a shortage of better foods[177, 257].

References   More on Edible Uses

Medicinal Uses

Plants For A Future can not take any responsibility for any adverse effects from the use of plants. Always seek advice from a professional before using a plant medicinally.
Alterative  Carminative  Haemostatic  Pectoral

Liquorice fern was employed medicinally by several native North American Indian tribes who used it especially as a treatment for a variety of chest complaints[257]. It is little, if at all, used in modern herbalism. The rhizomes are alterative, carminative, haemostatic and pectoral[257]. The raw rhizomes have been eaten, or an infusion has been used, in the treatment of coughs and colds, chest pains, shortness of breath and VD[257]. The roots have been chewed, and the juice swallowed, as a treatment for sore throats and the spitting or vomiting of blood[257]. A tea of the pounded boiled rhizomes, mixed with fir needles, has been used to treat measles[213]. Coughs have been treated by chewing and slowly swallowing the juice of the roasted rhizome[213]. The roots have been used in the treatment of colds and sore throats[256].

References   More on Medicinal Uses

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Other Uses

None known

Special Uses

Food Forest

References   More on Other Uses

Cultivation details

Tolerates short periods of drought and direct sunlight, but it prefers bright filtered light[200]. Plants can be grown on a drystone wall[200]. Members of this genus are rarely if ever troubled by browsing deer[233]. There are several named varieties selected for their ornamental value[200]. Polypodium glycyrrhiza hybridizes with P. calirhiza and with P. hesperium to produce sterile triploids with misshapen spores[270]. For polyculture design as well as the above-ground architecture (form - tree, shrub etc. and size shown above) information on the habit and root pattern is also useful and given here if available. An evergreen. The plant growth habit is a clumper with limited spread [1-2]. The root pattern is rhizomatous with underground stems sending roots and shoots along their length [1-2].

References   Carbon Farming Information and Carbon Sequestration Information

Temperature Converter

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Plants For A Future have a number of books available in paperback and digital form. Book titles include Edible Plants, Edible Perennials, Edible Trees,Edible Shrubs, Woodland Gardening, and Temperate Food Forest Plants. Our new book is Food Forest Plants For Hotter Conditions (Tropical and Sub-Tropical).

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Plant Propagation

Spores - best sown as soon as ripe on the surface of a humus-rich sterilized soil. Keep the compost moist, preferably by putting a plastic bag over the pot. 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 and then only in a very well sheltered position. Division in spring[200].

Other Names

If available other names are mentioned here

Native Range

TEMPERATE ASIA: Kamcatskij kraj,Russian Federation. NORTHERN AMERICA: Canada, Yukon, British Columbia, United States, Alaska, Idaho, Oregon, Washington, California,

Weed Potential

Right plant wrong place. We are currently updating this section. Please note that a plant may be invasive in one area but may not in your area so it’s worth checking.

Conservation Status

IUCN Red List of Threatened Plants Status :

Related Plants
Latin NameCommon NameHabitHeightHardinessGrowthSoilShadeMoistureEdibleMedicinalOther
Polypodium lineare Fern0.3 -  LMHSNM01 
Polypodium vulgarePolypody, Adders Fern, Golden Maidenhair Fern, Wall Fern, Common Polypod FernFern0.3 3-6 FLMHFSDM233

Growth: S = slow M = medium F = fast. Soil: L = light (sandy) M = medium H = heavy (clay). pH: A = acid N = neutral B = basic (alkaline). Shade: F = full shade S = semi-shade N = no shade. Moisture: D = dry M = Moist We = wet Wa = water.


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Botanical References


Links / References

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Readers comment

killah   Mon Dec 5 2005

Diversity? What are the different forms of licorice ferns? Are there any?

kevin   Sun Jan 29 2006

wow! this gives alot of info about it... i didnt know alot of this stuff.

F. Goffman   Thu Mar 23 2006

"It is little, if at all, used in modern herbalism." I think you have to get information from herbal chinese medicine (this plant is used a lot!) I have to say that altough I appreciate your efforts in providing information about plants, you should consider to take a close look at the information you are providing here which can be misleading. Best regards, F. Goffman

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