Mary Ellen (Mel) Harte,

Common watercress

Nasturtium officinale

Common watercress (Nasturtium officinale) is an invasive plant. It was first detected in United States in 1831.

Water cressis a fast-growing, aquatic or semi-aquatic, perennial herb. In arid regions of western states, it can alter function and block streams. It was reported to block water flow in springs in South Central Wisconsin.