This highly nutritious aquatic herb is a native of Europe, North Africa, and Asia, and has been cultivated as a salad plant since Roman times, but is now grown throughout the world in temperate zones.
Watercress has risen to a starring role in elaborate culinary preparations and is as beneficial for the health as much as the palate. It may be used as a garnish, in salads and sandwiches, added to herb butters, dressings, casseroles, soups and sauces for fish, and are also made into refreshing and nourishing teas.
Watercress leaves have a lovely mustardy bite that makes them natural bedfellows to strongly flavoured meats such as game. The leaves are most commonly served raw as a garnish to eggs or meat, or as part of a salad with orange segments. Watercress also makes a pleasingly peppery soup that is as good hot as it is chilled.
Low growing and trailing, the perennial European watercress is a member of the mustard family which is no surprise when you consider its delicious peppery taste. In its native habitat, watercress easily naturalises in springs, streams and even boggy ground, a habit that makes it a particularly undemanding plant to grow in the garden.
Hunting wild water cress is becoming a dangerous pastime with the prevalence of polluted waterways. Dirty streams makes watercress unfit to eat. (Remember - if you wouldn’t drink the water, you shouldn’t eat the watercress!) It is best to stay with a known cultivated source. Although it is available in some supermarkets, unless you can use an entire supermarket pack within a day or so, it goes floppy and has to be thrown out. Watercress is definitely worth growing at home.
Position: Although usually grown commercially in water, watercress can be grown in the garden soil provided it is given plenty of water and will crop from early summer till around early winter if protected with cloches during cold spells. You can also grow it in a container stood in a saucer of water. Plant 3 to 4 plants to a 30cm (12in) tub or pot and stand in a container with about 2 to 3in of water, in the shade. Keep the water constantly topped up to this level. The important thing to remember is to ensure the soil remains soaked at all times and to changing the water for fresh each day to avoid fungal infections.
Sowing: Sow successionally spring to autumn. Start seeds indoors in September to October or sow directly once the soil has begun to warm in October to November. Sow successionally each month until autumn. If you plant a sowing undercover late in the growing year, this will give fresh winter salad greens.
Sowing Indoors: Fill pots or trays with regular multipurpose compost; moisten by standing the container in water, then drain. Sow seeds by sprinkling quite finely onto the surface.
Cover the container with clear glass or plastic sheet. Once germinated, remove the glass. (If the nights are still cold, put the glass back on in the evening). Water daily, lightly at first, then thoroughly with a watering can once grown.
Sowing Direct: Sow in very shallow drills spread 7.5cm (3in) apart, and cover with a light covering of soil. You may wish to have your drill at the bottom of a small trench approximately 8 to 10cm (3-4in) deep for easier watering. Watercress seeds are quick to germinate anytime from 7 to 10 days. Thin out the seedlings finally to 10cm (4in) apart.
Cultivation: Keep weed free and water regularly and copiously throughout the season. Watercress produces small, white flowers in flat-topped clusters in summer to early autumn and, unless harvested frequently to prevent these flowers from forming, the leaves will become less tender and bitter.
Harvesting: Harvest once the plants have become well developed by trimming off tops of the shoots (about half its length) with sharp scissors. The stems will regenerate by producing side shoots. Carry on cutting as it grows. You can cut the same lengths when they re-grow too, but bear in mind that after 2 or 3 cuts the stalks start to get tough and the taste gets stronger as the plant get bigger. You can feed it with an organic fertiliser after the second cut to give it some final oomph. Sow successionally for tender young shoots.
Other Uses: Watercress plants are probably one of the best plants for the fish pond. Fish love to eat the shoots, the stems give the fish somewhere to hide; they play a role in water filtration and add to the natural beauty. Japanese Koi especially loves to eat this plant which should grow faster than they can possibly eat it if planted correctly.
Plants can be potted, or the rooted ends tucked into the rocks of a streambed or water fall, where water will flow past the plant. Plant 5 to 15cm (2 to 6in) deep.
Watercress is slow to start in the spring and could be eaten before it has a chance to flourish, but once the water temperature comes up in mid to late spring it quickly takes off. This is about the time that the appetite of fish, especially Koi increases dramatically. Watercress may have to be thinned at times. This plant has a root structure like a thick mat that may back up the water causing it to run over the side. Thinning the plants periodically removes toxins from the water that in an aquarium would be done with activated charcoal. Feed cuttings directly to the fish.
Nomenclature: In 1753 Linnaeus named this species Sisymbrium nasturtium-aquaticum and in 1812 the botanist Robert Brown renamed it Nasturtium officinale. Pliny records the Latin derivation of its generic name Nasturtium as Nasus tortus meaning "convulsed (or) wrinkled nose," undoubtedly referring to the plant's pungency. The species name officinale is Latin for 'of the shops', referring to the shops of the apothecary's, meaning that it has at some time been accepted as an official herb/drug.
Watercress is related to the garden flower nasturtium, but is from a different genus. It also shares a kinship with the mustard side of the cruciferous plants.
The English term ‘cress’, is from the Old English caerse and is akin to similar names throughout Europe such as cresson in French and crescione in Italian. These names may be derived from a common source. Latvian griezigs meaning ‘sharp’, or from the Indo-European root gres ‘devour’, Old Norse kras ‘delicacy’, Sanskrit grasati ‘he eats’ and Greek gran ‘gnaw’.
History: The European watercress has been eaten as part of the human diet as far back as history can record. Fortified with more than 15 essential vitamins and minerals, even since ancient times its health giving properties have been highly valued. Hippocrates, the father of modern medicine, is said to have deliberately located his first hospital beside a stream so that he could grow a plentiful and convenient supply of watercress with which to help treat his patients.
Watercress was one of the first plants cultivated by man and was used by Persian and Greek soldiers as a tonic to improve their health and stamina, and has been used through the ages as a spring tonic to tone the liver and cleanse the blood. Various cultures attributed powerful properties to it. The Romans and Anglo-Saxons thought watercress prevented hair loss, while Francis Bacon hailed the plant as an anti-ageing wonder product. The famed seventeenth-century English herbalist, Nicholas Culpepper, recommended this bitter, pungent, stimulant herb to "free the face" from blotches, spots and blemishes.