The European watercress - Nasturtium officinale, as been eaten as part of the human diet as far back as history can record. Fortified with more than 15 essential vitamins and minerals, even since ancient times its health giving properties have been highly valued. In fact Hippocrates - the Father of modern medicine - is said to have deliberately located his first hospital beside a stream so that he could grow a plentiful and convenient supply of watercress with which to help treat his patients.
Low growing and trailing, the perennial European watercress is a member of the mustard family which is no surprise when you consider its delicious peppery taste. In its native habitat, watercress easily naturalizes in springs, streams and even boggy ground, a habit that makes it a particularly undemanding plant to grow in the garden. Although it is easily propagated from seed, it is usually produced from stem sections which readily take root in wet soil. If you are feeling particularly lazy, you can throw a rooted stem into any body of slow moving water and can expect it to grow with no further involvement.
Although there is a lot of good identified with the consumption of watercress there is a word of warning to those of you who intend collecting watercress from the wild. Dirty streams can make watercress unfit to eat and so as a rule of thumb - if you wouldn't drink the water, you shouldn't eat the watercress. More importantly though is collecting watercress from bodies of water found near to where sheep and cattle are farmed. Water that has come into contact with their dung can cause watercress to become contaminated by liver flukes. Acute infection from liver flukes will cause severe abdominal pain, intermittent fevers, eosinophilia, malaise, and weight loss due to liver damage.