The areas in Essex with the highest number of infestations of the notorious Japanese knotweed has been revealed. 

The invasive plant can be a nightmare for homeowners and cause cracks in driveways, patios, paths, drains and even brick walls.

Experts say it can reduce a property’s value by up to 10 per cent if discovered within the boundary.

Environet, the UK’s leading specialist in the removal of Japanese knotweed, has revealed Southend has by far the biggest problem with the plant, with 29 separate infestations which span up to 4km.

Brentwood is the second worst with 16 infestations, and Colchester and Maldon joint third with 11 each.

Only Chelmsford and Clacton (both 10) were the other areas with double digit infestations in the county.

Following its winter hibernation, knotweed begins to grow in March or April, depending on the local ground temperature, reaching up to three metres in height by mid-summer.

A new heatmap has been set up to show the number of infestations in each postcode area in the UK.

Clacton and Frinton Gazette: Heatmap showing the worst affected areas in EssexHeatmap showing the worst affected areas in Essex

According to Environet’s research, approximately 5% of homes are currently affected by knotweed, either directly or indirectly (neighbouring an affected property), knocking around £20 billion off UK house prices.

Mat Day, Environet’s Regional Director for Essex, said: “Knowledge is power when it comes to Japanese knotweed and this heatmap is invaluable to homeowners and buyers who want to assess the risk in their local area.

“With the stamp duty holiday extended and lockdown restrictions beginning to ease, the property market is busier than ever – but failing to carry out the appropriate checks for knotweed can turn out to be an expensive mistake.

“Despite its fearsome reputation, with professional help, the plant can be dealt with and the value of a property largely restored.

"I’d urge anyone buying or selling a property, or homeowners wishing to preserve the value of their home, to be vigilant for signs of spring growth and check Exposed to see whether they live in a high-risk area.”