Water nut ∗ The 10 best care tips (Trapa natans)

Origin and Distribution

the Water nut (bot. Trapa natans) is an annual floating leaf plant from the genus of the water hazel family (bot. Trapaceae). The species was already widespread 65 million years ago, in the geological age of the Tertiary and thus at the same time as the dinosaurs. Even today the water nut thrives in the temperate to subtropical climates of Europe, Asia and Africa, but is Due to the intensive agriculture and the dwindling habitats in this country only rarely wild to be found. Therefore, the species is under strict nature protection and may not be taken from nature. In the trade you can get legal offspring, which are ideal for the near-natural planting of garden ponds.

use

Only offspring from Europe are suitable for planting in the garden pond at home, because the tropical varieties of the same name do not find suitable habitats here and therefore not thrive. Therefore, always pay attention to the proof of origin when buying! Most of the offspring of the water nut come from Hungary, southern France and Italy.

Water nuts can be planted individually or in groups, depending on the design requirements and the space available. The floating leaf plant also harmonizes very well with other domestic aquatic plants such as the heart-leaved pike herb (bot. Pontederia cordata, purple flowers), the European sea can (bot. Nymphoides peltata, yellow flowers) and the yellow pond rose (bot. Nuphar lutea).

Appearance and stature

Water nuts are deciduous, herbaceous aquatic plants that only grow for one summer. Their natural location is in stagnant waters, where they are anchored in the muddy bottom near the shore, primarily at a depth of 30 to 60 centimeters. The stalk, which is between one and three meters long and underwater, is rooted in the bottom of the lake, and the one in diameter Leaves up to 20 centimeters wide fan out from June to form a rosette of leaves lying on the surface of the water on.

leaves

The submarine petioles of the water nut are filled with air and therefore act as floating bodies. They provide the necessary buoyancy that keeps the green leaves on the surface of the water. The fan-shaped to diamond-shaped floating leaves of the species have a characteristic serrated edge and are arranged in rosettes on the surface of the water. The leaves turn red in the course of summer and then die in autumn. Also characteristic are the glands located on the underside of the leaves and on the stem, which presumably secrete an acid to protect against hungry aquatic animals.

Flowers and fruits

The inconspicuous, radially symmetrical flowers of the water nut are white and appear between July and August. The nut-like fruits of the plant develop on the stem. They have a hard, dark brown shell, are spiky and angular. The white core of the water nut fruits consists of around 20 percent starch and is cooked and edible. In fact, in earlier times the nutritious water nut was also considered a food in our country and it is still today, especially in Asian countries.

Toxicity

The white interior of the water nut is edible, but should only be eaten cooked or roasted. Raw fruits are considered poisonous, and parasites that are dangerous to humans tend to settle on the surface. Furthermore, the aroma, which is slightly reminiscent of chestnuts, only develops through cooking. The hard shell of the fruit is inedible, but can be easily opened with your fingers or a sharp knife and a little effort.

Location and soil

Water nuts only thrive in stagnant water that is warm and sunny. The plants are unsuitable for brooks and other flowing bodies of water, and it is better not to plant them in fish ponds either. The water and the subsoil should be rich in nutrients and low in lime - the water nut is only slightly lime-compatible. Water nuts feel most comfortable when the pond water is slightly acidic. You can do this by adding pressed peat soil. You can obtain this from specialist retailers. Only plant the plant in ponds that are between 40 and 60 centimeters deep.

Plant water nuts correctly

The easiest way to settle the water nuts in your garden pond is to sow them instead of planting them. The seeds - the nuts already described - are available from specialist gardeners. Simply sink them in the water in autumn, they will take root in the pond floor by themselves over the next few months and sprout in the following June. For an average garden pond, you calculate about two to three plants, which, however, should not be relocated near the pump.

In the spring, the specialist trade sometimes offers water nut plants, which you can plant out as follows:

• Place the plants on the calm surface of the water.
• Anchor them to the pond floor with a wire.

The long stems together with the roots then develop so that the plant has grown in the garden pond after a few weeks and can supply itself with nutrients.

Care tips

If the location requirements of the water nut - a sunny place in a standing freshwater pond with a water depth of up to 60 centimeters and a sandy-muddy underground - are not met, any maintenance measures are not necessary. The plant is hardy up to temperatures of at least minus 22 degrees Celsius.

Once sown, the annual water nut reproduces practically by itself over the years. As soon as the rosette of leaves dies in autumn, the nut fruits sink to the bottom of the pond and overwinter there. In spring, long, thin stems sprout from them and grow towards the surface of the water. From June the leaves develop, which finally lie on the water in a floating rosette.

Cut the water nut correctly

In order not to contaminate the water, you should cut off the withered leaves in small garden ponds or in the aquarium in autumn. In larger ponds, however, this precaution is not necessary.

Propagate the water nut

A targeted reproduction of the water nut is neither necessary nor possible. The plant reproduces by itself through the developed fruits, provided that the site conditions meet its requirements. The nut-like drupes, which are basically nothing more than specialized wintering organs represent, sink to the bottom of the pond in autumn and then drift to new ones in the following spring Plants out. Since every water nut forms several fruits during the season, a dense carpet can form on the garden pond over time. In order for the reproduction to succeed, you should cultivate the water nut as the only water plant, because other species would be competitors for the nutrients present in the water. However, since water nuts have a high nutritional requirement for the development of their fruits, they would with a further pond planting and the resulting drop in nutrient levels do not produce any fruits and simply die.

In autumn, the nuts can be removed before they sink. Keep them in a container of water until you need to use them again, although you will have to change it regularly. Under no circumstances should you use tap water for this, as water nuts do not tolerate lime. Instead, add collected rainwater or the like. ä. acidic, pressed peat soil added. In spring, the seeds can be pre-germinated in warm water and can then be set outside - However, before planting them out, slowly get them used to the climate change so that they are not shocked by the planting enter.

If the pond is already densely populated with water nuts, you can easily remove partial plants and transplant them into other ponds.

share

Water nuts cannot be divided as each nut only develops a floating stem with a rosette of leaves.

Diseases and pests

Diseases are unknown in water nuts, and the water plant is not attacked by pests. However, maintenance errors or an unsuitable location.

Species and varieties

Two varieties of the water nut are known. The Trapa natans var. natans is only legally available as offspring; Do not remove plants from growing plants in swampy areas. The offspring available in this country from Italy, Hungary and southern France usually grow well, but do not always produce fruits.

The species Trapa natans var, which comes from China. bispinosa, also known as Singhara water nut or Chinese two-thorn water nut, is also available from specialist retailers. The leaves of this variety are olive green and typically have seven reddish to reddish brown colored parallel veins on the leaf blade. The species is not hardy with us and must therefore be overwintered in artificial light in a winter garden or in a greenhouse.