Analysis by Horticulture.co.uk has found that confirmed cases of Japanese Knotweed have grown by 28% in the UK in just five years.
The study collated National Biodiversity Network figures from 49 local authorities in Britain – including the Environment Agency, National Trust, Botanical Society of Britain and Ireland, Natural England and others.
The invasive plant species was originally imported into Britain from Japan back in the nineteenth century, when engineers thought it would stabilise and beautify railway embankments.
It has since spread like wildfire across the UK, with more than 29,000 confirmed cases, which is growing in number each year.
The underground roots of the plant are known to be extremely difficult to eradicate completely, with the non-native species causing damage to watercourses.
The dense growth of Japanese Knotweed is damaging to watercourses, as it transposes native vegetation and causes damage to riverbanks. Its strong roots can also cause structural damage.
According to the data, there are a further 19,702 unconfirmed cases of Japanese knotweed, with thousands more in the UK likely to remain unreported.
A national eradication programme was proposed in 2015, but this was rejected by the government at the time due to its “prohibitively expensive” cost – estimated to be in the region of £1.5 billion.
