Practical
Plants

Nasturtium officinale

Watercress

a perennial member of the Nasturtium genus in the family Brassicaceae.

No photo available

Taxonomy and growth

Life cycle
perennial
Height
0.5 m
Spread
1 m
Fertility
Self fertile, Bees, Flies, Self
Flower type
hermaphrodite
Pollinators
Bees, Flies, Self

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.

Whilst the plant is very wholesome and nutritious, some care should be taken if harvesting it from the wild. Any plants growing in water that drains from fields where animals, particularly sheep, graze should not be used raw. This is due to the risk of it being infested with the liver fluke parasite[17][10]. Cooking the leaves, however, will destroy any parasites and render the plant perfectly safe to eat[10].

Edible uses

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

Leaves - raw or cooked[4][17][20][21][1][13]. Water cress is mainly used as a garnish or as an addition to salads, the flavour is strong with a characteristic hotness[3]. It has a reputation as a spring tonic, and this is its main season of use, though it can be harvested for most of the year and can give 10 pickings annually[9]. Some caution is advised if gathering the plant from the wild, see the notes above on toxicity. The leaves are exceptionally rich in vitamins and minerals, especially iron[5]. A nutritional analysis is available[7]. The seed can be sprouted and eaten in salads[3]. A hot mustardy flavour[K]. The seed is ground into a powder and used as a mustard[16][3]. The pungency of mustard develops when cold water is added to the ground-up seed - an enzyme (myrosin) acts on a glycoside (sinigrin) to produce a sulphur compound. The reaction takes 10 - 15 minutes. Mixing with hot water or vinegar, or adding salt, inhibits the enzyme and produces a mild but bitter mustard[9].

Product or use
Condiment
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.

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

Watercress is very rich in vitamins and minerals, and has long been valued as a food and medicinal plant[11]. Considered a cleansing herb, its high content of vitamin C makes it a remedy that is particularly valuable for chronic illnesses[11]. The leaves are antiscorbutic, depurative, diuretic, expectorant, purgative, hypoglycaemic, odontalgic, stimulant and stomachic[15][20][21][6][16][8][9]. The plant has been used as a specific in the treatment of TB[15]. The freshly pressed juice has been used internally and externally in the treatment of chest and kidney complaints, chronic irritations and inflammations of the skin etc[21]. Applied externally, it has a long-standing reputation as an effective hair tonic, helping to promote the growth of thick hair[10]. A poultice of the leaves is said to be an effective treatment for healing glandular tumours or lymphatic swellings[10]. Some caution is advised, excessive use of the plant can lead to stomach upsets[21][6]. The leaves can be harvested almost throughout the year and are used fresh[9].

Product or use
Antiscorbutic
Product or use
Depurative
Product or use
Diuretic
Product or use
Expectorant
Product or use
Hypoglycaemic
Product or use
Odontalgic
Product or use
Purgative
Product or use
Stimulant
Product or use
Stomachic
Product or use
TB

Material uses

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

The juice of the plant is a nicotine solvent and is used as such on strong tobaccos[20].

Product or use
Hair care

Environment

Range
Europe, including Britain, from Sweden and Denmark south and east to N. Africa and W. Asia.
Habitat
Stream margins, ditches, flushes etc with moving water[2][13], usually in chalk or limestone areas[18].
Light
full sun
Shade tolerance
no shade
Water
aquatic
Hardiness
Zone 6+
Soil textures
sandy, loamy, clay
Soil pH
acid, neutral, alkaline
Tolerates Nutritionally Poor Soil
No
Drought
intolerant

Propagation

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

Seed - sow spring in a pot emmersed to half its depth in water. Germination should take place within a couple of weeks. Prick out seedlings into individual pots whilst they are still small and increase the depth of water gradually until they are submerged. Plant out into a pond in the summer. Cuttings can be taken at any time in the growing season. Virtually any part of the plant, including a single leaf, will form roots if detached from the parent plant[19]. Just put it in a container of water until the roots are well formed and then plant out in shallow water.

Cultivation

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

Watercress is easily grown when given the correct conditions of slowly flowing clean water, preferably coming from chalky or limestone soils[12]. It prefers to grow in water about 5cm deep[14] with an optimum pH 7.2[5]. Plants can be grown in wet soil if the position is somewhat shaded and protection is given in winter, though the flavour may be hotter[13][14]. Hardy to about -15°c[5]. Watercress is often cultivated for its edible leaves, there are some named varieties[1][3]. The plant is very sensitive to pollution so a clean source of water is required[5]. Plants will often continue to grow all through mild winters. A fast-growing plant, the stems trail along the ground or float in water and produce new roots at the leaf nodes, thus making the plant very easy to propagate vegetatively[9]. Unfortunately, virus diseases have become more common in cultivated plants and so most propagation is carried out by seed[12]. This is a diploid species. It has hybridised naturally in the wild with the triploid species N. microphyllum to produce the sterile hybrid N. x sterilis which is also commonly cultivated as a salad crop[12]. The flowers are a rich source of pollen and so are very attractive to bees[20].

References

  1. Simons. New Vegetable Growers Handbook. Penguin 1977-00-00 ISBN 0-14-046-050-0

    ↩1↩2

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

    ↩

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

    ↩1↩2↩3↩4

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

    ↩

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

    ↩1↩2↩3↩4

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

    ↩1↩2

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

    ↩

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

    ↩

  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

  10. Phillips. R. & Foy. N. Herbs Pan Books Ltd. London. 1990-00-00 ISBN 0-330-30725-8

    ↩1↩2↩3↩4

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

    ↩1↩2

  12. Phillips. R. & Rix. M. Vegetables Macmillan Reference Books, London. 1995-00-00 ISBN 0 333 62640 0

    ↩1↩2↩3

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

    ↩1↩2↩3

  14. Thompson. B. The Gardener's Assistant. Blackie and Son. 1878-00-00

    ↩1↩2

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

    ↩1↩2

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

    ↩1↩2

  17. Mabey. R. Food for Free. Collins 1974-00-00 ISBN 0-00-219060-5

    ↩1↩2

  18. Larkcom. J. Salads all the Year Round. Hamlyn 1980-00-00

    ↩

  19. Muhlberg. H. Complete Guide to Water Plants. E. P. Publishing Ltd. 1982-00-00 ISBN 0-7158-0789-7

    ↩

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

    ↩1↩2↩3↩4

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

    ↩1↩2↩3↩4

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