Japanese knotweed hotspots in Wales are now identified

THE “top 10” locations in Wales affected by Japanese knotweed have been identified.

- LUCY JOHN

As the growing season for Japanese knotweed is in full swing, this invasive species can cause damage to properties, patios and paving, and decrease the value of land.

Invasive plant expert Environet has now disclosed the Welsh areas most affected by knotweed in 2025, using the latest figures from its online heatmap tool, Exposed: The Japanese Knotweed Heatmap. In total, there are 31,338 confirmed sightings of knotweed across Wales, equating to 3.9 instances per square mile, which is significantly higher than England's rate of 1.1 instances per square mile.

Now featuring more than 100,000 recorded instances of the UK's most pervasive plant, the map is updated with new confirmed sightings throughout the year, offering the most thorough online record of Japanese knotweed in the country.

The public can input their postcode to find out the number of sightings in their vicinity, with high-risk areas marked in yellow, orange or, in severe cases, red.