INFESTATIONS of an invasive plant species have been discovered.

A new tracking tool called Exposed: The Japanese Knotweed Heatmap found 12 cases of the plant within 4km of Brighton’s i360.

Nic Seal, founder of Japanese knotweed firm Environet who created the map, said: “This heatmap will help us build a nationwide picture of the Japanese knotweed problem and give the general public the information they need to assess the risk in their local area.

“There are a number of knotweed infestations around East and West Sussex, particularly in coastal locations such as Brighton, Bexhill and Hastings.”

There were also 32 infestations within 4km of Hastings town centre.

Knotweed can grow as deep as three metres underground, undermining concreted pathways and patios.

It can also grow under a buildings’ foundations and affect their structure.

It was described by the Environment Agency as “indisputably the UK’s most aggressive, destructive and invasive plant”.

The map was designed to tell homeowners and potential homebuyers about the potential risk to their property.

Mr Seal said: “Exposed will be a useful tool for those buying and selling property in the area and local residents who want to be aware of infestations near their homes which could spread, putting their property at risk.”

Environet advised Sussex residents to be vigilant, particularly when buying or selling a property.

It encouraged people to contribute to the heatmap by reporting knotweed infestations using the Add Sighting feature and attaching a photograph of the plant so it can be verified by experts.

The plant has red or purple shoots which appear from the ground and grow rapidly, forming hard canes.

As they grow, they will form heart-shaped leaves and turn green.

The plant grows at a rate of about 10cm a day from May until July, when it is fully grown and can stand up to three metres tall.

Knotweed blooms in late summer, when it becomes covered in tiny creamy-white flowers. During the late autumn, the leaves fall and the canes turn brown and die, although they remain standing.