Around here it grows wild in many slow clear running streams.
Not too far from me there is a spring called Cress Spring. Forty years ago there was a green house over the spring branch and they grew the stuff commercially for St Louis restaurants.
When I was a kid I'd go camping with my grand parents in Alley Spring St Park. My grandma had a wooden box she put the things in that needed to be refrigerated, and dropped the box in the spring branch attached to a rope, tied to a tree. When I was sent to retrieve something for dinner I had a standing order to pick a bunch of watercress for salads that evening.
I ate a lot of watercress in my youth.
THANX RICH