A fast-growing, aquatic or semi-aquatic, perennial plant native to Europe and Asia, and one of the oldest known leaf vegetables consumed by humans. is a perennial semiaquatic vegetable plant known for its spicy foliage that's popular in salads and similar dishes a peppery, tangy flavor. The hollow stems of watercress are floating, and the leaves are pinnately compound. Small, white and green flowers are produced in clusters.