Water Hyacinth, is a free floating aquatic plants rather easy to grow. It is native to tropical and in South America. They have feathery roots and beautiful rounded leaves.
Each spike carries several flowers. In the right environment it grows profusely and rapidly. I grew them in a tub on a roof garden and before you knew they would feel the tub.
In natural environments it is treated as a invasive plants, it can rapidly take over a body of water specially with abundance of nutrients.
However the plant also has many benefits. It has strong tolerance for toxins and is used in waste waters to clear toxins such as cyanide, arsenic and is known to increase nitrification.