Practical
Plants

Rumex hydrolapathum

Great Water Dock

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Taxonomy and growth

Genus
Rumex
Life cycle
perennial
Height
1.8 m
Fertility
Wind
Flower type
hermaphrodite
Pollinators
Wind

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.

Plants can contain quite high levels of oxalic acid, which is what gives the leaves of many members of this genus an acid-lemon flavour. Perfectly alright in small quantities, the leaves should not be eaten in large amounts since the oxalic acid can lock-up other nutrients in the food, especially calcium, thus causing mineral deficiencies. The oxalic acid content will be reduced if the plant is cooked. People with a tendency to rheumatism, arthritis, gout, kidney stones or hyperacidity should take especial caution if including this plant in their diet since it can aggravate their condition[9].

Edible uses

Young leaves - cooked[6][2][5]. Seed - raw or cooked. It can be ground into a powder and used as a flour[1]. The seed is small and rather fiddly to harvest.

Plant part
Leaves
Plant part
Seed

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 is antiscorbutic and strongly astringent[11]. It is harvested in early spring and dried for later use[11]. The green leaves are said to be an excellent application for ulcers of the eyes[11].

Product or use
Antiscorbutic
Product or use
Astringent
Product or use
Ophthalmic

Material uses

The roots contain tannin. In cultivated plants, those grown on dry land contained 6 - 8% tannin whilst those grown in water contained 12.4 - 21.6%[8]. The dried and powdered root makes a good tooth cleaner[11]. Dark green to brown and dark grey dyes can be obtained from the roots of many species in this genus, They do not need a mordant[3].

Product or use
Dye
Product or use
Tannin
Product or use
Dental care

Environment

Range
Western Europe, including Britain, from Scandanavia south and east to Spain, Italy and S. Russia.
Habitat
Near ponds and streams, also in shallow water, avoiding acid conditions[4].
Light
full sun
Shade tolerance
light shade
Water
aquatic
Hardiness
Zone 6+
Soil textures
sandy, loamy, clay
Soil pH
neutral, alkaline
Tolerates Nutritionally Poor Soil
No
Drought
intolerant

Propagation

Seed - sow spring in situ. Division in spring.

Cultivation

Requires a moist or wet soil, also succeeding in shallow water. Avoids acid conditions in the wild. A very important food plant for the caterpillars of many species of butterfly[10].

References

  1. Kavasch. B. Native Harvests. Vintage Books 1979-00-00 ISBN 0-394-72811-4

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

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  3. Grae. I. Nature's Colors - Dyes from Plants. MacMillan Publishing Co. New York. 1974-00-00 ISBN 0-02-544950-8

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  4. Clapham, Tootin and Warburg. Flora of the British Isles. Cambridge University Press 1962-00-00

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

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  6. Hedrick. U. P. Sturtevant's Edible Plants of the World. Dover Publications 1972-00-00 ISBN 0-486-20459-6

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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. Rottsieper. E.H.W. Vegetable Tannins The Forestal Land, Timber and Railways Co. Ltd. 1946-00-00

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

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  10. Carter D. Butterflies and Moths in Britain and Europe. Pan 1982-00-00 ISBN 0-330-26642-x

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

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