A HEATMAP revealing the hotspots for one of the UK's most invasive plants has been unveiled - with more than 20 reported occurrences in Lyme Regis and Dorchester.

With its ability to push through cracks in concrete, patios, drains and even walls, Japanese knotweed has entered its spring growth phase and experts are warning homeowners to be vigilant.

Using data from an online tracker, Exposed: the Japanese Knotweed Heatmap, created by Environet, reveals the latest hotspots in the UK. The map shows that Lyme Regis is the worst affected area in Dorset, with 29 infestations within a four kilometre radius. Dorchester is the second worst affected area, with 21 infestations. By comparison, there are 82 infestations in the Ventnor area of the Isle of Wight.

Swanage and Wareham Voice: Japanese knotweed growing on a river bankJapanese knotweed growing on a river bank

Following its winter hibernation. knotweed begins to grown in March or April and can reach up to three metres in height by mid-summer. Homeowners spending more time in their garden may notice purple or red asparagus-like shoots now emerging from the ground and quickly growing into lush green shrubs with heart or shovel-shaped leaves and pink flecked stems.

The plant was brought to the UK during the Victorian era as an ornamental species and it was also found to be useful as stabilising the ground at railway cuttings. However, it soon became a horticultural pest.

It is unlawful to cause it to grow in the wild or to allow knotweed from your own property to invade neighbouring land.

Swanage and Wareham Voice: Japanese knotweedJapanese knotweed

Emily Grant, Environet's regional director for Dorset, 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 an 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."