Japanese knotweed is a gardeners nightmare: it grows fast and pushes other species away, which also means that the birds and insects that those plants need to survive are in danger of disappearing.
Invasive plant specialist Environet has revealed Lancashire’s knotweed hotspots for 2025 using the latest data from its online tracker, Exposed: The Japanese Knotweed Heatmap.
In the national Japanese knotweed hotspots list, Lancashire is the 4th worst affected county in England, with a total of 8,612 verified knotweed sightings in Lancashire so far this year, or 7.25 incidences in every 1mi².
Now populated with over 100,000 known incidences of the UK’s most invasive plant, Enivornet’s map is updated with new verified sightings throughout the year, providing the most comprehensive online record of Japanese knotweed in the country.
Members of the public can enter their postcode to discover the number of sightings nearby, with hotspots highlighted in yellow, orange or in the worst cases red, helping them understand the level of risk posed to their home or one they wish to buy.
They can also help populate 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.
Take a look below at the 10 biggest hotspots for Japanese knotweed in Lancashire below...
1. Japanese knotweed hotspots Lancashire
Take a look at the 10 areas of Lancashire with the highest Japanese knotweed cases | BELGA MAG/AFP via Getty Images
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