Water chestnut - Trapa natans

Water chestnut - Trapa natans


Water chestnut is a perennial aquatic plant native to much of Asia that has long been introduced to Europe and North America. It consists of a dense rosette of floating, toothed, fan-shaped leaves, bright green on the upper side, with thin down on the underside. 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 ranging in color from white to deep pink, which float above the leaves. Roots that sink into the ground develop below the rosette. In summer, each flower becomes a woody fruit, which contains a single fleshy seed.

This plant likes sunny exposure but also thrives very well in other conditions. Trapa natans suffers from very cold winters and where temperatures are very low, it is generally grown as an annual.

The water chestnut has an edible tuber that is used in many areas as a food. In Italy, the tuber of Trapa natans can be used as an ingredient in risottos and other dishes but it can also be used raw, fried or ground into flour.


As mentioned in the previous paragraph, this plant prefers locations in full sun, although it develops smoothly in any conditions. 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.


The roots of the trapa natans essentially have the function of anchoring the plant to the ground, and they do so in any terrain; however, the plant does not like water rich in limestone, preferring water with a slightly acid pH. The roots can reach great depths in the water, reaching up to 5 meters in height.


It happens by seed; the ripe seeds should be stored for the whole winter in a container filled with water, in a cool place away from frost. In spring the seeds are planted in a soil consisting of peat and sand in equal parts, in containers that must be kept under water until the seedlings appear, which must be planted in autumn or in the spring of the following year. Being a plant that expands rapidly and constantly, the water chestnut can also be multiplied by division, separating a portion of the plant from the mother plant until a new one is obtained.

Parasites and diseases

As for the parasites and diseases of this plant, Trapa natans is hardly attacked and there are no particular infestations for this species.

Water chestnut - Trapa natans: Uses in herbal medicine

One of the uses that is made of this plant is the herbal one. The water chestnut can in fact be used by those who love natural cures and phytotherapy for different purposes. For example, with its leaves and fruits it is possible to obtain different preparations. The leaves have soothing and refreshing properties and allow the skin to relax after sunburn and redness.

The seeds are instead used for digestive disorders, such as diarrhea, against which they seem to have an excellent effect.

Video: Water Caltrop BAT NUT Taste Test (October 2021).