Practical
Plants

Glycyrrhiza glabra

Liquorice

a perennial member of the Glycyrrhiza genus in the family Leguminosae.

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Taxonomy and growth

Life cycle
perennial
Height
1.2 m
Spread
1 m
Fertility
Insects
Flower type
hermaphrodite
Pollinators
Insects

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.

This section contains historical Plants For A Future notes marked noncommercial.

A gross overdose of the root can cause oedema, high blood pressure and congestive heart failure[19][17].

Edible uses

This section contains historical Plants For A Future notes marked noncommercial.

Root - raw or used as a flavouring. The source of liquorice powder that is extracted and used in sweets, baked goods, ice cream, soft drinks etc[18][13][1][7], it is also used medicinally. A sweet and delicious flavour, but the root is very fibrous[K]. The root contains glycyrrhizin, a substance that is 50 times sweeter than sucrose[5][7][10]. The dried root is often used for chewing, it is excellent for teething children and also as a tooth cleaner[18][13]. A tea made from the roots is an excellent thirst quencher[9]. The powdered root is also used as a sweetener in other herb teas[7]. The leaves are used as a tea substitute in Mongolia[7].

Plant part
Root
Product or use
Sweetener
Product or use
Tea

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.

This section contains historical Plants For A Future notes marked noncommercial.

Liquorice his one of the most commonly used herbs in Western herbal medicine and has a very long history of use, both as a medicine and also as a flavouring to disguise the unpleasant flavour of other medications[14]. It is a very sweet, moist, soothing herb that detoxifies and protects the liver[10] and is also powerfully anti-inflammatory, being used in conditions as varied as arthritis and mouth ulcers[12]. The root is alterative, antispasmodic, demulcent, diuretic, emollient, expectorant, laxative, moderately pectoral and tonic[14][19][9][15][4][6]. The root has also been shown to have a hormonal effect similar to the ovarian hormone[18]. Liquorice root is much used in cough medicines and also in the treatment of catarrhal infections of the urinary tract[14]. It is taken internally in the treatment of Addison's disease, asthma, bronchitis, coughs, peptic ulcer, arthritis, allergic complaints and following steroidal therapy[10]. It should be used in moderation and should not be prescribed for pregnant women or people with high blood pressure, kidney disease or taking digoxin-based medication[10]. Prolonged usage raises the blood pressure and causes water retention[18][10]. See also the notes above on toxicity. Externally, the root is used in the treatment of herpes, eczema and shingles[10]. The root is harvested in the autumn when 3 - 4 years old and is dried for later use[14][10].

Product or use
Alterative
Product or use
Antiinflammatory
Product or use
Antispasmodic
Product or use
Demulcent
Product or use
Diuretic
Product or use
Emollient
Product or use
Expectorant
Product or use
Laxative
Product or use
Pectoral
Product or use
Tonic

Material uses

This section contains historical Plants For A Future notes marked noncommercial.

The plant yields a substance that is used for etching steel sections in photomicrographic work[5]. Extracts from the root are used as a foaming agent in beers and fire extinguishers[10]. A fibre obtained from the roots is used for insulation, wallboard, boxboard etc[14][5]. The fibres can be used after the medicinal and flavouring constituents of the root have been removed[14].

Product or use
Fibre

Environment

Range
Europe - Mediterranean.
Habitat
Dry open places[16], especially in sandy places near the sea[2].
Light
full sun
Shade tolerance
light shade
Water
moderate
Hardiness
Zone 8+
Soil textures
sandy, loamy
Soil pH
acid, neutral, alkaline
Tolerances
high wind
Wind
Yes
Tolerates Nutritionally Poor Soil
No
Drought
intolerant

Propagation

This section contains historical Plants For A Future notes marked noncommercial.

Pre-soak the seed for 24 hours in warm water and then sow spring or autumn in a greenhouse[8]. Prick out the seedlings into individual pots when they are large enough to handle, and grow them on for their first winter in a greenhouse. Plant out in late spring or early summer when in active growth. Plants are rather slow to grow from seed[10]. Division of the root in spring or autumn. Each division must have at least one growth bud. Autumn divisions can either be replanted immediately or stored in clamps until the spring and then be planted out[8]. It is best to pt up the smaller divisions and grow them on in a cold frame until they are established before planting them out in the spring or summer.

Cultivation

This section contains historical Plants For A Future notes marked noncommercial.

Requires a deep well cultivated fertile moisture-retentive soil for good root production[8]. Prefers a sandy soil with abundant moisture and does not flourish in clay[14]. Slightly alkaline conditions produce the best plants[10]. The plant thrives in a maritime climate[18]. Plants are hardy to about -15°c[8]. Liquorice is often cultivated for its edible root which is widely used in medicine and as a flavouring. There are some named varieties[7]. The ssp. glandulifera grows in Russia and produces adventitious roots up to 10 cm thick[3]. Yields of 10 - 12 tonnes per hectare were considered good in the early 20th century, this only being attained in the fourth year of growth[14]. Unless seed is required, the plant is usually prevented from flowering so that it puts more energy into producing good quality roots[10]. The bruised root has a characteristic sweet pungent smell[11]. Plants are slow to settle in and do not produce much growth in their first two years after being moved[14]. The young growth is also very susceptible to damage by slugs and so the plant will require some protection for its first few years[K]. A fairly deep-rooting plant, the roots are up to 120cm long[14]. It can be difficult to eradicate once it is established[10]. This species has a symbiotic relationship with certain soil bacteria, these bacteria form nodules on the roots and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby[8].

References

  1. Polunin. O. Flowers of Europe - A Field Guide. Oxford University Press 1969-00-00 ISBN 0192176218

    ↩

  2. Bianchini. F., Corbetta. F. and Pistoia. M. Fruits of the Earth.

    ↩

  3. Brouk. B. Plants Consumed by Man. Academic Press 1975-00-00 ISBN 0-12-136450-x

    ↩

  4. Mills. S. Y. The Dictionary of Modern Herbalism.

    ↩

  5. Hill. A. F. Economic Botany. The Maple Press 1952-00-00

    ↩1↩2↩3

  6. Stuart. Rev. G. A. Chinese Materia Medica. Taipei. Southern Materials Centre

    ↩

  7. Facciola. S. Cornucopia - A Source Book of Edible Plants. Kampong Publications 1990-00-00 ISBN 0-9628087-0-9

    ↩1↩2↩3↩4↩5

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

    ↩1↩2↩3↩4↩5

  9. Lust. J. The Herb Book. Bantam books 1983-00-00 ISBN 0-553-23827-2

    ↩1↩2

  10. 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↩11↩12

  11. Genders. R. Scented Flora of the World. Robert Hale. London. 1994-00-00 ISBN 0-7090-5440-8

    ↩

  12. Chevallier. A. The Encyclopedia of Medicinal Plants Dorling Kindersley. London 1996-00-00 ISBN 9-780751-303148

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  13. Harrison. S. Wallis. M. Masefield. G. The Oxford Book of Food Plants. Oxford University Press 1975-00-00

    ↩1↩2

  14. Grieve. A Modern Herbal. Penguin 1984-00-00 ISBN 0-14-046-440-9

    ↩1↩2↩3↩4↩5↩6↩7↩8↩9↩10

  15. Uphof. J. C. Th. Dictionary of Economic Plants. Weinheim 1959-00-00

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  16. ? Flora Europaea Cambridge University Press 1964-00-00

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  17. Frohne. D. and Pf�nder. J. A Colour Atlas of Poisonous Plants. Wolfe 1984-00-00 ISBN 0723408394

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  18. Chiej. R. Encyclopaedia of Medicinal Plants. MacDonald 1984-00-00 ISBN 0-356-10541-5

    ↩1↩2↩3↩4↩5

  19. Launert. E. Edible and Medicinal Plants. Hamlyn 1981-00-00 ISBN 0-600-37216-2

    ↩1↩2

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