Practical
Plants

Lactuca perennis

Perennial Lettuce

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Taxonomy and growth

Genus
Lactuca
Life cycle
perennial
Height
0.6 m
Spread
0.3 m
Fertility
self fertile
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.

Although no specific mention of toxicity has been seen for this species, many plants in this genus contain a narcotic principle, this is at its most concentrated when the plant begins to flower. This principle has been almost bred out of the cultivated forms of lettuce but is produced when the plant starts to go to seed[2].

Edible uses

Leaves - raw or cooked[12][14][16][1][4]. The leaves are often blanched to reduce any bitterness. They are fairly acceptable raw in salads (even without being blanched), especially in late winter and spring when the flavour is quite mild[K]. The leaves do become much more bitter in the summer, however, especially as the plant comes into flower[K].

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.

Although we have seen no specific reports for this species, most if not all members of the genus have a milky sap that contains the substance 'lactucarium' and can probably be used as the report below details[K]. The whole plant is rich in a milky sap that flows freely from any wounds. This hardens and dries when in contact with the air[13]. The sap contains 'lactucarium', which is used in medicine for its anodyne, antispasmodic, digestive, diuretic, hypnotic, narcotic and sedative properties[18][8][14][3][6][9][11]. Lactucarium has the effects of a feeble opium, but without its tendency to cause digestive upsets[13], nor is it addictive[17]. It is taken internally in the treatment of insomnia, anxiety, neuroses, hyperactivity in children, dry coughs, whooping cough, rheumatic pain etc[11]. Concentrations of lactucarium are low in young plants and most concentrated when the plant comes into flower[11]. It is collected commercially by cutting the heads of the plants and scraping the juice into china vessels several times a day until the plant is exhausted[13]. An infusion of the fresh or dried flowering plant can also be used[18]. The plant should be used with caution, and never without the supervision of a skilled practitioner. Even normal doses can cause drowsiness whilst excess causes restlessness[11] and overdoses can cause death through cardiac paralysis[17][18]. Some physicians believe that any effects of this medicine are caused by the mind of the patient rather than by the medicine[9]. The sap has also been applied externally in the treatment of warts[10].

Environment

Range
S. Europe.
Habitat
Rocky or other dry places, especially on calcareous soils[12][15].
Light
full sun
Shade tolerance
no shade
Water
moderate
Hardiness
Zone 6+
Soil textures
sandy, loamy
Soil pH
acid, neutral, alkaline
Drainage
well drained
Tolerates Nutritionally Poor Soil
No
Drought
intolerant

Propagation

Seed - sow April in a greenhouse, only just covering the seed. Germination is usually fairly quick When they are large enough to handle, prick the seedlings out into individual pots and grow them on in the greenhouse for their first winter. Plant them out into their permanent positions in late spring or early summer, after the last expected frosts. Division in spring. It is best to pot up the divisions and keep them in a lightly shaded position in a cold frame until they are growing away well. Plant them out in the summer. Root cuttings in spring[K].

Cultivation

Prefers a light well-drained sandy loam and a sunny position[5]. Plants are hardy to about -25°c[5].

References

  1. Tanaka. T. Tanaka's Cyclopaedia of Edible Plants of the World. Keigaku Publishing 1976-00-00

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  2. Triska. Dr. Hamlyn Encyclopaedia of Plants. Hamlyn 1975-00-00 ISBN 0-600-33545-3

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

    ↩

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

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  5. Phillips. R. & Rix. M. Perennials Volumes 1 and 2. Pan Books 1991-00-00 ISBN 0-330-30936-9

    ↩1↩2

  6. Emboden. W. Narcotic Plants Studio Vista 1979-00-00 ISBN 0-289-70864-8

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

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

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  9. Weiner. M. A. Earth Medicine, Earth Food. Ballantine Books 1980-00-00 ISBN 0-449-90589-6

    ↩1↩2

  10. Foster. S. & Duke. J. A. A Field Guide to Medicinal Plants. Eastern and Central N. America. Houghton Mifflin Co. 1990-00-00 ISBN 0395467225

    ↩

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

    ↩1↩2↩3↩4

  12. Vilmorin. A. The Vegetable Garden. Ten Speed Press ISBN 0-89815-041-8

    ↩1↩2

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

    ↩1↩2↩3

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

    ↩1↩2

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

    ↩

  16. Usher. G. A Dictionary of Plants Used by Man. Constable 1974-00-00 ISBN 0094579202

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

    ↩1↩2

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

    ↩1↩2↩3

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