Watercress (Nasturtium officinale) is a water plant that can be found throughout the United States, southern Canada, Europe and Asia. It's actually native to Europe and Asia.
Watercress grows in shallow running water where it normally forms dense mats. Its stems usually have 3 to 9 small oval leaves and grow 4 to 10 inches high. It flowers from April to October. Watercress flowers are small and white and occur in long clusters like many other mustards.
As one of our most nutritious wild foods, watercress is rich in calcium, beta carotene and iron. It also contains a variety of vitamins and minerals including vitamins C, B1, B2 and E.
Watercress was traditionally used to treat coughs, gout and arthritis. It's an expectorant and also a diuretic, so it helps to relieve fluid retention.
Watercress is best used fresh but can be kept indefinitely in water if the water is changed daily. It's good raw in salads or as a cooked green and can be used any way cultivated mustard is used. It pairs well with the following:
Although watercress typically occurs all year, the cold of winter usually beats it back to a point that makes it difficult to gather in quantity, and the heat of summer makes it hot and bitter. Nasturtium leaves and flowers make a good substitute in the summer.
Watercress grows in water that is slightly alkaline. Here in the Southern Appalachians our water and soil are acidic, so we typically only find watercress in areas downstream of spring boxes or other concrete structures that raise the pH of the water.
The easiest way to harvest is to cut its stems at waterline with scissors. It's also easy to gather by pulling clumps out by the roots if you don't mind cutting the roots off later. It's important, especially when eating watercress raw, to take it only from water that's been tested and is known to be clean. Otherwise, harmful pathogens and toxins can be contracted when eating.