Watercress
Nasturtium officinale

Family: Brassicaceae or Cruciferae

What it is like

Bloom Color: White. Main Bloom Time: Early summer, Late spring, Mid spring. Form: Spreading or horizontal, Variable spread.

Nasturtium officinale is a PERENNIAL growing to 0.5 m (1ft 8in) by 1 m (3ft 3in) at a fast rate. See above for USDA hardiness. It is hardy to UK zone 6 and is not frost tender. It is in flower from May to October, and the seeds ripen from July to October. The species is hermaphrodite (has both male and female organs) and is pollinated by Bees, flies. The plant is self-fertile. It is noted for attracting wildlife. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It cannot grow in the shade. It prefers wet soil and can grow in water.

Height (m): 0.5

Where it is found

Stream margins, ditches, flushes etc with moving water, usually in chalk or limestone areas.

Europe, including Britain, from Sweden and Denmark south and east to N. Africa and W. Asia.

Conservation Status:

Countries/locations it is found in

How it is used

Food

Rating: 4

Leaves - raw or cooked. Water cress is mainly used as a garnish or as an addition to salads, the flavour is strong with a characteristic hotness. 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. 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. A nutritional analysis is available. The seed can be sprouted and eaten in salads. A hot mustardy flavour. The seed is ground into a powder and used as a mustard. 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.

Seed: includes nuts, cereals, peas and beans.

Condiment: the various plants that are used as flavourings, either as herbs, spices or condiments.

Medicine

Rating: 3

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

Antirheumatic: Treats rheumatism.

Antiscorbutic: A plant rich in vitamin C that is used to counteract scurvy.

Appetizer: Improves the appetite

Depurative: Eliminates toxins and purifies the system, especially the blood.

Diuretic: Acts on the kidneys, promoting the flow of urine.

Expectorant: Clears phlegm from the chest by inducing coughing.

Hypoglycaemic: Reduces the levels of sugar in the blood.

Miscellany: Various medicinal actions that need more clarification.

Odontalgic: Treats toothache (temporary measure only) and other problems of the teeth and gums.

Purgative: A drastic laxative causing a cleansing or watery evacuation of the bowels, usually with a griping pain.

Stimulant: Excites or quickens activity of the physiological processes. Faster acting than a tonic but differing from a narcotic in that it does not give a false sense of well-being.

Stomachic: Aids and improves the action of the stomach.

TB: Plants used in the treatment of tuberculosis

Vitamin C: Plants good for their vitamin C content

Other

Rating: 2

The juice of the plant is a nicotine solvent and is used as such on strong tobaccos. A dynamic accumulator gathering minerals or nutrients from the soil and storing them in a more bioavailable form - used as fertilizer or to improve mulch.

Hair: Plants used as hair shampoos, tonics, to treat balding etc.

Miscellany: A rag-bag of items that are difficult to categorise.

Attracts Wildlife: Plants noted for attracting wildlife

Dynamic accumulator: Plants that gather minerals or nutrients from the soil and store them in a more bioavailable form and in high concentration in their tissues. Used as fertilizer or to improve mulch.

Food Forest: Plants for Edible Forest Gardens and Food Forests.

How it is grown

Landscape Uses:Container. Watercress is easily grown when given the correct conditions of slowly flowing clean water, preferably coming from chalky or limestone soils. It prefers to grow in water about 5cm deep with an optimum pH 7.2. 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. Hardy to about -15°c. Watercress is often cultivated for its edible leaves, there are some named varieties. The plant is very sensitive to pollution so a clean source of water is required. 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. Unfortunately, virus diseases have become more common in cultivated plants and so most propagation is carried out by seed. 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. The flowers are a rich source of pollen and so are very attractive to bees. Special Features: Attractive foliage, Edible, Not North American native, Wetlands plant, Flower characteristics are unknown. For polyculture design as well as the above-ground architecture (form - tree, shrub etc. and size shown above) information on the habit and root pattern is also useful and given here if available. The plant growth habit is a runner spreading indefinitely by rhizomes or stolons. The root pattern is fibrous dividing into a large number of fine roots.

Propagating it: 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. Just put it in a container of water until the roots are well formed and then plant out in shallow water.

Best place to grow: Pond; Bog Garden;

Habit: Perennial

Hardiness: 3-11

Growth: Fast

Soil: Light (sandy), medium, heavy (clay)

Shade: No shade

Moisture: Wet, water

Things to keep in mind

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. Cooking the leaves, however, will destroy any parasites and render the plant perfectly safe to eat. May inhibit the metabolism of paracetamol .

Its other names

Local names

Synonyms

Rorippa nasturtium-aquaticum. (L.)Hayek. Sisymbrium nasturtium-aquaticum.