Watercress grows well and wild in clean running water and flooded swampy places, and especially around the pure water of the Doshi River.
We went camping to Doshi Village, where the river is famous for its clean waters. Watercress has been cultivated in the village on account of the clean running waters.
Watercress goes by the name of creson in Japan (like the French word). Watercress belongs to the genus Nasturtium, although the common nasturtium is quite different. Botanists also give Roripa and Radicula as alternative generic names. Watercress is a perennial plant grown for the pungent leaves and young stems which are widely used for garnishing and in salads. The smooth compound leaves have three to a dozen nearly round 1-inch-wide leaflets. Leaves and stems are partially submerged during growth.
Commercially, watercress is grown in unshaded shallow pools of flowing clean water. Doshi village produces 1/3 of the watercress produce in Japan and is the key watercress producer in Japan.The amount of consumption expands rapidly caused by change of the Japanese eating habits. Consumption has been expanding rapidly due to the change in the Japanese diet in adopting more western foods, including raw salads.
The plant belongs to the mustard family (Brassicaceae) and is native to Eurasia. It is naturalized throughout North America in cool, flowing streams where it grows submerged, floating on the water, or spread over mud surfaces. See picture of watercress here.