Curly waterweed Lagarosiphon major / Elodea densa

Status Non-native, invasive
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A non-native invasive plant.

This waterweed, and others similar to it are widely sold across Britain – often labelled simply as ‘oxygenating plants’ or ‘pondweeds’. They are aquatic plants that like to live completely submerged under water and all can grow up to 3m in length. In the wild, they have spread very quickly across the UK.

What's the problem?

They grow faster and outcompete most native species and so reduce the biodiversity of waterways. Although they are sold for their ‘oxygenating’ quality, they can cause big fluctuations in the amount of oxygen available in the water and this can be harmful to invertebrates and fish. In slow flowing rivers, drainage channels and canals, their dense growth often impedes flow and exacerbates flooding.

This species is listed on Schedule 9 of the Wildlife and Countryside Act in England and Wales therefore, it is also an offence to plant or otherwise cause to grow this species in the wild.