- Water chestnut: origin and properties
- Different shapes of the water chestnut
- Plant water chestnut
- Care for the Water Nut
- Harvesting and Use of the Water Nut
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The water chestnut (Trapa natans) is a very special aquatic plant. We will tell you how you can plant and care for the water chestnut in your own pond.
The water chestnut is an endangered beauty that can also decorate your garden pond. Find out below how to cultivate and care for this special aquatic plant. We also show how the fruits of the water chestnut can be used.
Water chestnut: origin and properties
The water chestnut (Trapa natans) is classified botanically in the subfamily water chestnut plants (Trapaceae) of the loosestrife family (Lythraceae). Although the names of the water chestnut and the water chestnut (Eleocharis dulcis) sound very similar, the two are unrelated and visually very different from each other.
Originally, the water chestnut comes from the temperate and subtropical zones of Europe, Asia and North Africa. Today it is still weakly distributed in the entire Mediterranean area. In Germany, the last stocks are threatened with extinction, which is why the water chestnut has been under nature protection and has been on the red list since 1987. It was an important food source for people in the Neolithic Age and is still occasionally used in Asian cuisine today.
The water chestnut plant is a deciduous annual floating plant. It is anchored to the ground by a 1 to 3 meter long main shoot and by the barbs of the water chestnut fruit. The herbaceous leaves are held at the water surface by an air-filled stalk. They are fan-shaped to diamond-shaped and arranged in a rosette-like manner around the petiole. The plants can reach a diameter of about 20 cm. The formation of the leaves begins in June. There are acid-secreting glands on the underside of the leaves and on the stems, which serve to protect against feeding. Small, inconspicuous, white flowers are formed from July to late August or early September. The water chestnut is self-pollinating, which means that the flowers can be pollinated by their own pollen. As the fall progresses, the leaves turn a beautiful red and diegradually off. Secondary roots are formed in pairs on the main shoot, which support the water chestnut in photosynthesis.
The fruits of the water chestnut are dark brown, hard-shelled nuts. They grow along the stem and form two to four sharp thorns at the ends. The thorns are later used, like an anchor, to fix it to the bottom of the water. This allows a new plant to grow next year without aborting. Inside is a white, starchy core. The core is ripe between September and October and will germinate the following year when it is warm enough. In addition to being spread by water, the nuts can also be spread by birds or by humans.
Different shapes of the water chestnut
There are generally two types of water chestnut:
- Trapa natans var. natans: The native to Europe Trapa natans var. natans is the water chestnut that grows best in our country. Since it is threatened with extinction, the seed comes exclusively from the offspring. Some plants do not produce fruit.
- Trapa natans var. bispinosa: The originating from Asia Trapa natans var. bispinosa (also called 'Chinese Two-Thorned Water Chestnut' or 'Singhara Water Chestnut') produces olive-green leaves with reddish or reddish-brown veins. Because of the shorter summer here, there is not enough time to form fruit. She needs the tropical climate for that.
Plant water chestnut
The natural habitats of the water chestnut are stagnant waters, low-lime but nutrient-rich backwaters, humus mud lakes and ponds and the lower third of the Danube from Serbia. Because of its need for heat, it does not grow at higher altitudes. If you want to cultivate the water chestnut in the garden pond, you need a muddy-sandy pond bottom and an average depth of about 60 cm. In addition, it should be warm and sunny. Slightly acidic pond water is preferred by the water chestnut, but is not a must.
To sow the water chestnut in the pond, it is sufficient to place the nuts near the desired spot on the bottom of the pond. The plant then anchors itself and grows. For smaller ponds, 2 to 3 nuts are enough to achieve a beautiful plant appearance. Group planting is also possible without further ado. The yellow water lily (Nuphar lutea), the European water lily, is particularly suitable for this(Nympoides peltata) or heart-leaved pikeweed (Pontederia cordata) well suited.
Note: Planting in a fish pond is less suitable because of the acid that the plant secretes as a protection against feeding. Nevertheless, this is possible without endangering the fish. However, water chestnuts only sprout once, which is why the plants react very sensitively to damage caused by feeding and can die.
The water chestnut multiplies by itself through the nuts formed. The ripe fruits fall off as soon as the annual plant dies and are distributed through the water. They are frost-resistant and hardy at temperatures down to -22 °C. The next year they anchor themselves in the ground and sprout again on their own. If you want to increase the water nut in a targeted manner, you can harvest ripe nuts and sow them the following year. Propagation via sections, comparable to the propagation of cuttings in wood, is not possible.
Tip: The water chestnut can also be kept as a single plant in the aquarium. Here, an ideal nutrient supply for the water chestnut can be guaranteed and there is no competition from other plants. However, the water chestnut does not produce any fruit in the aquarium. If you want to keep fish in the aquarium at the same time, you should definitely check their compatibility with the acid of the water chestnut plant.
Care for the Water Nut
If the water chestnut is planted in a location that meets its needs, it does not require any further care throughout the year. In small ponds and in aquariums, some or all of the leaves should be removed in autumn as soon as the plant dies, depending on the size of the pond or aquarium. In this way, the water is not overly polluted with rotting biomass. There are no problems with this in large ponds.
Because it is an annual plant that dies back in autumn, the water chestnut cannot be overwintered as a whole plant, only as seeds. The seeds can be fished out of the pond and overwintered in a bowl of water or simply left in the pond.
Harvesting and Use of the Water Nut
The ripe fruits of the water chestnut can be harvested without any problems when the plant dies. They can then be detached from the main shoot and collected.
You can eat the kernels of the water chestnut. As mentioned at the beginning, the water chestnut was an important one in the Neolithic periodsource of protein. It is still occasionally used in Asia today. Due to its rarity, however, it has almost completely disappeared from European cuisine. Raw consumption is strongly discouraged as numerous harmful parasites can settle on the surface. Anyone who cooks the nut breaks down the toxins it contains and kills parasites. The core can then be eaten without hesitation, but the shell remains inedible due to its hardness. The aroma of the kernel is comparable to that of chestnuts.
In addition, the water chestnut is said to have a healing effect, which has not yet been proven.
Are you still looking for other plants for your garden pond? Here you will find pond plants for every water depth.