CLEVEDON and Weston have been identified as hotspots for the invasive Japanese knotweed plant that could see the value of your home drop drastically.

According to invasive plant specialist Environet, there are 22 known infestations in Clevedon and 20 in Weston, with only Bath (138 cases) suffering more cases in Somerset.

Environet has analysed the latest data from its live online tracker to reveal this year’s areas worst hit by Japanese knotweed.

With almost 58,000 known infestations of the UK’s most invasive plant and charting its spread across the country, Exposed: The Japanese Knotweed Heatmap alerts homeowners and homebuyers to the risk level in their local area.

Users can enter their postcode directly into the map to discover the number of verified knotweed sightings within a 4km radius, with hotspots highlighted in yellow, orange or, in the worst cases, red.

They can also add sightings by uploading a photo to be verified by experts.

With 359 known infestations across Somerset, there is one occurrence of Japanese knotweed in every 10 square kilometre.

It usually emerges in spring and grows rapidly to up to 2.5 metres high by mid-summer.

It is identifiable by its hard, bamboo-like canes and distinctive shield-shaped bright green leaves which grow in a zigzag pattern along the stem.

Mature plants flower in August, becoming covered in clusters of delicate tasselled creamy-white flowers.

All the knotweed plants in the UK are female, so it usually spreads accidentally through the movement of soil or gardening waste, or via rivers and streams when pieces of rhizome break off and take hold in new locations.

Homeowners are at risk from potential damage to their property, outbuildings and gardens, and also from legal risks arising from encroachment or when properties are sold.

While it isn’t illegal to have knotweed growing on your land, if it is allowed to cross a boundary into an adjacent property, legal disputes can arise between neighbours.

Nic Seal, founder of Environet, said: “Vigilance is the best way to protect your property from the risks posed by Japanese knotweed.

"Make sure you know what knotweed looks like and how it differs from other common garden weeds like ivy and bindweed, so you can keep an eye out for it in your garden and neighbourhood.

"Knotweed is easily identifiable during summer, but as we head through the autumn and into winter, the above-ground growth dies back and it becomes much harder to spot.

"It’s also easier to conceal, so anyone viewing a property to buy should be extra careful.

“There are lots of horror stories out there but the with professional help, knotweed can be successfully treated and a property’s value can be largely restored.”