There are two main varieties: the Fontaine watercress and the Alenois watercress. The watercress of Fontaine, as its name implies it, grows in water. The Alenois watercress, a perennial plant, is sown from March to September. Harvesting begins 6-7 weeks after planting and continues until frost.
Watercress is fairly resistant to disease but may be affected by damping-off (a fungus that will weaken the plant, stems of seedlings may also become thin and tough, boots sometimes rot completely or back to just discoloured stumps). Subsequently, this disease results in slower growth of the plant, which can even lead to the death of the latter. Watercress is a vegetable but also a leaf.