Watercress is an aquatic plant, Nasturtium officinale, that is grown for its edible foliage. It’s a member of the mustard or cabbage family, Brassicaceae. Also called cress, it’s native to Eurasia and now naturalized in temperate regions and mountains of North America.
Watercress is an aquatic or semi-aquatic plant. It’s a creeping perennial that is found in cool streams, springs, brooks, canals, ditches and on low ground that is typical of wetlands. It may be floating on top of the water, submerged underneath the surface or on mud flats adjacent to flowing water. Full sun is required as watercress will not grow in the shade. It needs clean running water so it likely won’t be found in fertilizer-laden runoff from crop fields.
Be careful when picking wild cress as runoff from farms, fields and streets may affect the quality of the leaves. Leaves can be contaminated with liver flukes or other parasites in locations adjacent to fields used for grazing livestock. Pesticides and farm chemicals may contaminate cress growing near crop fields. Runoff from roads and sewers may contaminate watercress growing in canals and ditches. It’s better to select organically grown watercress. To assure a safe crop it’s cultivated in tanks for its tangy leaves and young shoots.
Watercress has pinnately compound, entire leaves with three to nine oval leaflets having the terminal leaflet larger than the rest. It attains a height of only four to ten inches. The stems are hollow which help the plant to float in water. Cress roots easily at leaf nodes along the stems and tends to form mats. Flowers are small, about a quarter-inch in diameter, with four white petals. The blooming period is spring through early summer.
The leaves are typically eaten raw or used as a garnish. It’s eaten most often in spring, although it may grow all year-long in the right conditions, and so, be consumed nearly any time of year. The leaves are rich in vitamin C and vitamin A and are tossed in salads or eaten on sandwiches instead of lettuce. Shredded leaves are whipped into sandwich spreads to enjoy the pungent, tangy, mustard-like flavor.
Sometimes watercress is eaten cooked. Leaves are simmered with butter or butter and cream and eaten as a vegetable. It’s added to other cooked greens for a hot, pungent taste. Cream of watercress soup is made with leaves and a white sauce.
Watercress has been the source of many health claims. Further research should be conducted to verify its reputed antioxidant, diuretic, digestive, stimulant, expectorant and anti-cancer properties.