UK: The invaders lurking in our ponds


The UK's scattered ponds represent a vital network of wildlife havens. But there are hidden threats lurking in the water that a new campaign hopes to eradicate.

Be Plant Wise is a coordinated effort by Defra, NNSS (GB Non-native Species Secretariat), Oata (Ornamental fish), HTA (Horticultural trade association) and Plantlife to stop the spread of invasive pond plants from over-running the countryside where they can smother native plants, clog waterways, compromise flood defences, and reduce oxygen.

Five of the most common plants that pose a risk and highlighted by the campaign are:

New Zealand pigmyweed (Crassula helmsii), water fern (Azolla filiculoides), floating pennywort (Hydrocotyle ranunculoides), water primrose (Ludwigia grandiflora), and parrot's feather (Myriophyllum aquaticum). They look innocuous enough, but can cost millions to eradicate each year and all pond owners and water users can help prevent them spreading by following a few simple tips such as composting excess pond plants, not giving away pond plants, not pumping pond water in other watercourses, and most importantly, knowing what you grow.

There are galleries of most of the plants on the NNSS website, but here's a quick guide of some to avoid!

Floating pennywort

floating pennywort floating pennywort close-up

Parrot's feather

parrot's feather parrot's feather close-up

Water primrose

water primrose water primrose

Water fern

water fern in canal water fern close-up

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