NATIONAL Trust rangers and volunteers across the Lake District are spending more than 350 days tackling the growing problem of non-native invasive species.

These ‘alien invasions’ manifest themselves in lakes, along riverbanks, and in the wider countryside.

Rhododendron is one of the species tackled. They produce several million seeds each year and see them dominating areas.

National Trust rangers have been tackling rhododendrons for more than 15 years in places like Windermere’s west shore, Monk Coniston and Wray Castle.

Due to their tenacity, rhododendron prevent native flowers from growing and can impact on trees by damaging the surrounding habitat.

Their leaves and buds contain toxic chemicals that are indigestible to grazing animals and poisonous to humans and bees.

And Himalayan Balsam might be good for bees but, if not kept under control, could destroy the area’s diverse natural habitats.

Himalayan Balsam is one of the most widespread of the invasive species as it travels down watercourses. As well as forcing out native flowering plants, it also leads to riverbank erosion.

Cumbria was home to the first UK wild sighting of the Eastern Asia native ‘Japanese Rose’ some 90 years ago.

Since then the small pink flower has invaded some of the area’s valued habitats including Sandscale Haws near Barrow-in-Furness where it spreads quickly and out-competes native species by preventing sunlight from reaching them.

Rangers and volunteers have to cut, burn and treat the area each year to avoid regrowth.

New Zealand pigmyweed is almost impossible to eradicate and grows 200 times faster than normal pond plants.

With the growing popularity of wild swimming and newer watersports such as stand up paddle boarding in Cumbria’s lakes, the biggest risk is that pigmyweed will be spread accidentally into pristine waters like Buttermere, Crummock Water and Loweswater.

New Zealand pigmyweed can get caught on or wrapped around anything so is easily transferred from one location to another.

The invasion of pigmyweed has got worse over the last 10 years, particularly in Derwentwater where the thick mats of vegetation it creates swamp out the native plant species and threaten the survival of rare freshwater fish.

Anyone interested in finding out more about supporting the work of the National Trust in the Lake District should visit https://www.nationaltrust.org.uk/lakedistrict