The water chestnut is a perennial aquatic plant native to much of Asia, which has long been introduced in Europe and North America. It consists of a dense rosette of floating, toothed, fan-shaped leaves, bright green on the upper page, with thin hair on the lower page. The leaves are attached by means of a long spongy stem. The plant produces real patches of leaves that float on the water in areas where the current is less intense and strong. Lakes and ponds are typical areas where this plant grows in abundance.
In spring it produces solitary flowers of various colors from white to deep pink, which float above the leaves. The roots that sink into the ground develop underneath the rosette. In summer each flower becomes a woody fruit, which contains a single fleshy seed.
This plant loves sunny exposure but it grows very well also in other conditions. Trapa natans suffers from very cold winters and where temperatures are very harsh it is generally grown as an annual.
The water chestnut has an edible tuber which is used in many areas as a food. In Italy the tuber of Trapa natans can be used as an ingredient in risotto and other dishes but it can also be used raw, fried or reduced in flour.
As mentioned in the previous paragraph, this plant prefers positions in full sun, even if it develops without problems in any condition. In places with very cold winter the plant is grown as an annual, the plants die completely with the arrival of winter, but every spring a new rosette of leaves develops from the seeds.