The number of infestations of a harmful weed has been documented across Berkshire.

Japanese Knotweed is an invasive plant known to cause damage by spreading its roots below ground, bursting through weak or cracked concrete, foundations and other structures.

It grows throughout the summer months and invasive plant specialist Environet has analysed the latest data to reveal this year’s Japanese knotweed hotspots - finding 377 reports in the county.

Reading has been reported to have 148 infestations of Japanese Knotweed.

While Slough has 59 and Maidenhead 27.

Wokingham has fewer infestations, with just 26 reported, followed by Ascot which saw 23 reported cases.

There are known to be almost 58,000 known infestations, with Japanese knotweed being the UK’s most invasive plant.

Homeowners and homebuyers have been warned about the risks associated with the weed,

Japanese knotweed usually emerges in March or April and grows rapidly to reach up to 2.5 metres in height 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.

Knotweed does not produce viable seeds as all the plants in the UK are female, so it is usually spread 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. 

According to Environet, tackling knotweed costs the UK economy nearly £250 million.

Whilst 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.

Similarly, when properties are sold, sellers are asked a direct question about whether knotweed is present, even if hidden beneath the ground or within 3 metres of the boundary, and those who fail to declare it can be sued by their buyer for misrepresentation.

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.”