Nasturtium microphyllum
| Nasturtium microphyllum | |
| Light: |  |
| Moisture: |  |
| Hardiness: | 6 |
| Soil pH: | 5.6-8.4 |
| Self Pollinated | |
| Height: | 2' |
| Width: | 3' |
| Native to: | |
| Edible Rating: |  |
| Medicinal Rating: |  |
| Tea: | Yes |
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Nasturtium microphyllum (common name: watercress)
Propagation: 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[1]. Just put it in a container of water until the roots are well formed and then plant out in shallow water.
Cultivation: Watercress is easily grown when given the correct conditions of slowly flowing clean water, preferably coming from chalky or limestone soils[2]. It prefers to grow in water about 5cm deep[3] with an optimum pH 7.2[4]. 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[5][3].
Plants are hardy to about -15°c[4], they tolerate somewhat lower temperatures than the closely related N. officinale[4].
Watercress is often cultivated for its edible leaves, there are some named varieties[6][7]. The plant is very sensitive to pollution so a clean source of water is required[4]. 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[8]. Unfortunately, virus diseases have become more common in cultivated plants and so most propagation is carried out by seed[2].
This is a triploid species. It has hybridised naturally in the wild with the diploid species N. officinale to produce the sterile hybrid N. x sterilis which is also commonly cultivated as a salad crop[2].
The flowers are a rich source of pollen and so are very attractive to bees[9].
Range: Europe, including Britain, to W. Asia.
Habitat: Stream margins, ditches, flushes etc with moving water[10][5], usually in chalk or limestone areas[11].
Edibility: Leaves - raw or cooked[12][13][9][14][6][5]. Exceptionally rich in vitamins and minerals, especially iron[4]. The leaves are mainly used as a garnish or as an addition to salads, the flavour is strong with a characteristic hotness[7].
The seed can be sprouted and eaten in salads[7]. A hot flavour.
The seed is ground into a powder and used as a mustard[15][7]. 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[8].
Medicinal: Antiscorbutic, diuretic, expectorant, purgative, stimulant, stomachic[16][14][17][15]. Use with caution[17].
Pollinators: Bees, flies, self
Soil: Can grow in light, medium, and heavy soils.
Flower Type: Hermaphrodite
Links
References
- ↑ Muhlberg, Helmut. Complete Guide to Water Plants. Sterling Publishing, 1982.
- ↑ 2.0 2.1 2.2 Phillips, Roger and Martyn Rix. Vegetables. Macmillan Reference Books, 1995.
- ↑ 3.0 3.1 Thompson, Robert. The Gardener's Assistant. Blackie and Son, 1878.
- ↑ 4.0 4.1 4.2 4.3 4.4 Huxley, Anthony. The New Royal Horticultural Society Dictionary of Gardening. MacMillan Press, 1992.
- ↑ 5.0 5.1 5.2 Vilmorin-Andrieux. The Vegetable Garden. Ten Speed Press.
- ↑ 6.0 6.1 Simons, Arthur. New Vegetable Growers Handbook. Penguin, 1977.
- ↑ 7.0 7.1 7.2 7.3 Facciola, Stephen. Cornucopia - A Source Book of Edible Plants. Kampong Publications, 1990.
- ↑ 8.0 8.1 Bown, Deni. Royal Horticultural Society Encyclopaedia of Herbs and Their Uses. Dorling Kindersley, 1995.
- ↑ 9.0 9.1 Chiej, Roberto. Encyclopaedia of Medicinal Plants. MacDonald, 1984.
- ↑ Clapham, Arthur and Tom Tootin, Edmund Warburg. Flora of the British Isles. Cambridge University Press, 1962.
- ↑ Larkcom, Joy. Salads all the Year Round. Hamlyn, 1980.
- ↑ Hedrick, Ulysses. Sturtevant's Edible Plants of the World. Dover Publications, 1972.
- ↑ Mabey, Richard. Food for Free. Collins, 1974.
- ↑ 14.0 14.1 Launert, Edmund. Edible and Medicinal Plants. Hamlyn, 1981.
- ↑ 15.0 15.1 Uphof, Johannes. Dictionary of Economic Plants. Weinheim, 1959.
- ↑ Grieve, Margaret. A Modern Herbal. Penguin, 1984.
- ↑ 17.0 17.1 Lust, John. The Herb Book. Bantam Books, 1983.