Environment Agency maintenance teams are more than half way through a 6-week programme, removing the invasive non-native species (INNS) Floating Pennywort to try to stop it spreading further.

Using floating weed harvesters and lifters, the Environment Agency teams have removed more than 1000 tonnes of wet cut invasive weed, while another team followed up behind, hand removing and spraying the smaller pieces of weed.

Floating Pennywort is normally found in tropical aquaria and garden ponds. It is, however, being found more and more in rivers across the country. It forms very dense mats of vegetation which can grow rapidly (up to 20 centimetres per day) out from the riverbanks.

Darren Trumper, Environment Agency Operations Delivery Team Leader said:

“Floating Pennywort has become a major problem for us all in the River Cam and Ely Ouse. Some of the Floating Pennywort mats we are removing from the riverbanks along the Ely Ouse are 22 metres long and 10 metres wide, and can be a depth size of about 30 millimetres. In one location the teams removed a mat weighing 1.7 tonnes”

An especially worrying factor in the infestation is the invasion of the River Cam Washes, which is a Site of Special Scientific Interest (SSSI) and crucial to all kinds of wildlife.

Native to North America, Floating Pennywort is a fast growing invasive species of freshwater plant. It is widespread and well established in the south and east of England and appears to be spreading rapidly north and westwards.

This makes it one of many high priority invasive non-native plant species in Great Britain.

The Environment Agency is also asking for help to track down the problem plants by using a free App called ‘PlantTracker’ available from the website http://PlantTracker.naturelocator.org .