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Floating pennywort

Introduced to the UK in the 1980s by the aquatic nursery trade, this fleshy-stemmed plant uses its roots to inter-weave a floating mat of lush foliage.

Floating pennywork covering most of canal with boat moored at side Floating pennywort, copyright GBNNS

But don’t be fooled by this former resident of tropical aquaria and garden Cows eating floating pennywort in fieldponds, this highly invasive plant is a real problem. It grows very rapidly in late summer – up to 20cm per day – and is responsible for swamping waterways, crowding out native plants and taking oxygen from fish and insects.

Like the Japanese knotweed, it also has the ability to grow from miniscule fragments, making its removal incredibly difficult and expensive.

Last date edited: 29 July 2015