Watercress (Nasturtium nasturtium-aquaticum, N. microphyllum) are fast-growing, aquatic or semi-aquatic, perennials native from Europe to central Asia and one of the oldest known leaf vegetables consumed by human beings. These plants are members of the Family Brassicaceae or cabbage family, botanically related to garden cress and mustard — all noteworthy for a peppery, tangy flavor.

The stems of watercress are floating and the leaves are pinnately compound. Watercresses produce small, white and green flowers in clusters.

Nasturtium officinale Ait. f. and Sisymbrium nasturtium-aquaticum L. are synonyms of N. nasturtium-aquaticum. Nasturtium officinale var microphyllum (Boenn. ex Reich.) Thellung is a synonym of N. microphyllum (ITIS, 2004). These species are also listed in some sources as belonging to the genus, Rorippa, although molecular evidence shows that the aquatic species with hollow stems are more closely related to Cardamine than Rorippa (Al-Shehbaz & Price, 1998). Watercresses are not related to the flowers in the genus, Tropaeolum (Family Tropaeolaceae), popularly known as "nasturtiums".

Watercress cultivation

Cultivation of watercress is practical on both a large scale and a garden scale. Being semi-aquatic, watercress is well-suited to hydroponic cultivation, thriving best in water that is slightly alkaline. It is frequently produced around the headwaters of chalk streams. In many local markets the demand for hydroponically-grown watercress exceed supplies. This is due in part to the fact that cress leaves are unsuitable for distribution in dried form and can only be stored for a short period.

However (in the UK at least), the packaging used by supermarkets using sealed plastic bags under some internal pressure (a plastic envelope containing moisture and pressurised (inflated) to prevent crushing of contents) has allowed the distribution of watercress (and sometimes a mixture of it with other salad leaves). This has allowed national availability with a once purchased storage life of 1 - 2 days in chilled / refrigerated storage.

If unharvested, watercress can grow to a height of 50-120 cm. Also sold as sprouts, the edible shoots are harvested days after germination.

Like many plants in this family, the foliage of watercress becomes bitter when the plants begin producing flowers.

Food value

Watercress contains significant amounts of iron, calcium and folic acid, in addition to vitamins A and C. In some regions watercress is regarded as a weed, in other regions as an aquatic vegetable or herb. Where watercress is grown in the presence of animal waste, it can be a haven for parasites such as the liver fluke Fasciola hepatica.

Many benefits from eating watercress are claimed, such as that it acts as a mild stimulant, a source of phytochemicals and antioxidants, a diuretic, an expectorant, and a digestive aid.
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article on Watercress
Allspice Aloe Ambrosia Herbs Amchur (mango powder) Angelica (Angelica archangelica) Anise Annatto Apple Mint Arrowroot Artemisia vulgaris Asafoetida Asarum europaeum Ashwagandha Australian desert raisin Bacopa monnieri Balm of Gilead Barberry (Berberis) Basil (Ocimum basilicum) Bay Laurel Bay leaves Bergamot (Monarda didyma) Bison grass (Hierochloe odorata) Bistort (Persicaria bistorta) Bitters Black cardamom Black limes Pepper (black, white, and green) Blue Cohosh Bog Labrador Tea Boldo Bolivian Coriander (Porophyllum ruderale) Boneset (Eupatorium) Borage (Borago officinalis) Camomile - German Chamomile Camomile - Roman Chamomile Candle nut Caper (Capparis spinosa) Caraway Cardamom Carob Pod Catsear Cayenne pepper Celery (Celery seed) Chervil (Anthriscus cerefolium) Chili powder Chives (Allium schoenoprasum) Cinnamon Cloves Coriander Cumin Curry powder Dill (Anethum graveolens) Echinacea Fennel (Foeniculum vulgare) Five-spice powder (Chinese) Garam masala Garden cress Garlic Garlic chives Geum Herbes de Provence Horseradish Jamaican jerk spice Juniper Land cress Lavender (Lavandula spp.) Lemon balm (Melissa officinalis) Lemon Basil Lemon mint Lemon Myrtle (Backhousia citriodora) Licorice Long pepper Lovage (Levisticum officinale) Marjoram (Origanum majorana) Mint (Mentha spp.) Mustard Mustard seed Nepeta (Catnip) Nutmeg (and Mace) Oenothera Oregano (Origanum vulgare) Paprika Parsley (Petroselinum crispum) Peppermint Pineapple weed Poppy seed Rosemary (Rosmarinus officinalis) Saffron Sage Sichuan pepper Star anise Tamarind Tandoori masala Tarragon (Artemisia dracunculus) Thyme Turmeric Vanilla (Vanilla planifolia) Watercress