Giant knotweed (Potamogeton polygonifolius) is a versatile native oxygen plant that is perfect for shallow ponds. The plant is known for its leathery, floating leaves that partly cover the water surface, providing shade for fish and amphibians. At the same time, the plant provides oxygenated water, making it a valuable addition in natural and ecologically designed ponds.
Centipede pondweed is a perennial aquatic plant in the pondweed family. This species feels at home in shallow ponds where the water is poor in calcium and nutrients, and slightly acidic in nature. Typical growing sites include peat ponds, dune pools and moist lowlands on sandy soils. It is a rooting plant that functions well in clear and calm water. The name "knotweed" refers to the plant's ability to form new rosettes via nodes on the stem when dry.
It grows 25 to 70 cm tall and forms both submerged and floating leaves. The floating leaves are oval to oblong in shape, leathery and sometimes bronze-coloured. Between May and August, the plant blooms with inconspicuous green flowers that rise above the water in a spike-shaped inflorescence.
The plant grows from an underground rhizome and copes well with varying water levels. This characteristic makes the plant very suitable for shallow areas that sometimes temporarily dry up. When temperatures rise again, the plant spontaneously resumes its development.
Thanks to its combination of oxygen production and shading, knotweed is an ideal choice for shallow ponds. The shade under the leaves helps keep the water cooler, which is beneficial for fish and prevents excessive algae growth.
The plant is suitable for pond baskets or directly in the soil, in substrate, sand or pond soil. Its robust growth and adaptability make it a low-maintenance, self-sustaining plant.
Good combinations:
For a healthy pond environment, we recommend 4 to 5 bunches per 1,000 litres of water. Calculate here how many oxygen plants you need in the pond.
This plant is perennial and can grow for years, provided conditions remain suitable.
Yes, the plant is completely hardy. In mild winters, it remains partly green.
No, centipede pondweed gets all its nutrition from the pond water itself.
Maintenance is minimal. If necessary, older or dead parts can be removed in autumn, but this is often not strictly necessary.
Giant knotweed is available from our sales partner Vijvermeester.nl.
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