Water-cress is an evergreen aquatic plant that grows in thick drifts in shallow, clear water (especially fast-flowing streams) all around the UK. Traditionally hand-picked from the wild as a useful salad addition, it became popular in the 18th century, and is now cultivated on a commercial scale.
How to identify?
Water-cress has green, divided leaves with rounded leaflets, and hollow stems which float on the surface of the water. Small white and green flowers appear in clusters from May to October.