Rorippa nasturtium-aquaticum


Family: Brassicaceae

Weed class: monitor list
Native to: Western Asia, India, Europe, and Africa
Legal listings:

In the United States, it is listed by 46 states as noxious and invasive.

Why Is It a Noxious Weed?

This plant is on the monitor list. Please contact its sponsor Cathy Lucero to report locations or for more information.

How would I identify it?

General Description

This trailing, aquatic plant tends to look like a tangled cluster of leaves and stems above the water. This plant is a culinary herb known for a peppery flavor.

Flower Description

Clustered, 3-5 mm long white flowers appear above the water from March through October.

Leaf description

Older leaves are compound leaves, composed of 3 to 11 leaflets, and 4 to 12 cm long. Young leaves are simple.

Stem description

Generally 10-60cm long, watercress has a fragile, fleshy stem that trails and is upright at the ends. 

Where does it grow?

Watercress is generally found in cold, flowing streams and shallow fresh water.

How Does it Reproduce?

Watercress reproduces from rooting stem fragments and seeds.

For More Information

USDA APHIS page on watercress

Washington State Ecology page on watercress

Pacific Northwest Aquatic Invasive Species Profile on watercress

Invasive.org page on watercress

Additional Photos