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Battle against floating plant invasion on River Stort

An outbreak of Floating Pennywort – a plant which can cause flooding and kill off native plants and fish – is sections of the River Stort between Bishop’s Stortford and Harlow.

We've currently got a specialist team on the river, killing it off and lifting it out of the water.

Incredibly, floating pennywort is capable of growing up to 20cm in a day and is able to double its weight in as little as three days, and unlike Himalayan Balsam and Giant Hogweed, it will continue to grow during the winter months unless there is a hard frost.

Clog the river

The plant can cause flooding by blocking overflow sluices and disrupting the ecology of the river - smothering local plants and killing fish. It spreads in large clumps over the surface of the water depriving the water and riverbed of both light and oxygen. If left unchecked, it can clog the river and prevent navigation, fouling the propellers of boats.

Rick Jones, Canal & River Trust customer operations supervisor, said: “Pennywort may look a bit like a load of floating lettuces, but it's actually pretty horrible stuff. It is a priority that we tackle this plant growth, because it can threaten our ability to control flooding, maintain fish stocks and protect the local ecology. We've acted quickly, so are confident that we'll get the better of it.”

Last Edited: 02 December 2014

photo of a location on the canals
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