With the Japanese knotweed growing season now well underway, we’ve mined data from our interactive online tracker, Exposed: The Japanese Knotweed Heatmap, to reveal the national knotweed hotspots for 2022. 

Populated with almost 55,000 known occurrences of knotweed, Exposed is the most comprehensive online record of knotweed infestations, charting the spread of the plant across the country. Just enter your postcode to discover the number of sightings nearby, with hotspots highlighted in yellow, orange and, in the worst cases, red. 

The national Japanese knotweed hotspots for 2022 are: 

1. Bolton, Greater Manchester (684 infestations within 4km radius)
2. Bristol (475)
3. St Helens, Mersyside (441)
4. Blackburn, Lancashire (407)
5. Capel Garmon, Snowdonia, Wales (398)
6. Llanelli, South Wales (389)
7. Cardiff, Wales (361)
8. Rotheram, Yorkshire (306)
9. Steatham, SW Lodnon (300)
10. Nottingham (225)
11. Sheffield (225)

What to do if you think you have Japanese knotweed

• If you find a suspicious-looking plant and you’re not sure what it is, check out the identification guide on our website or use the free ID service by sending a photo to [email protected]
• Once knotweed is confirmed, commission a survey to find out the extent of the infestation, where it originated and the best way to tackle it
• Arrange professional treatment, usually herbicide or excavation, and always be sure to secure an insurance-backed guarantee for the work
• If you’re buying a property and you want to be sure it’s clear of knotweed, particularly if it’s located in or near a hotspot, arrange a detection dog survey.

To view Japanese knotweed infestations in your area or to report a sighting by uploading a photo to be verified by our experts, please visit Exposed.