Japanese knotweed map: records near your postcode

From 71 datasets shared on the NBN Atlas, the UK's biodiversity database: the Botanical Society of Britain and Ireland's Plant Atlas and verified iRecord sightings, local environmental records centres, river and invasive species projects, the Environment Agency and members of the public using the INNS Mapper app. We use only records shared under open licences that allow it.

Records show where someone has found knotweed and reported it. Most private gardens are never surveyed, and some areas have far more recorders than others, so no record nearby doesn't mean there's no knotweed.

A record in the area doesn't, on its own. Surveyors follow the RICS standard, which looks at knotweed on the property and on neighbouring land within 3 m of the boundary. Our guide to Japanese knotweed treatment explains the four RICS categories and what lenders ask for.

Of the three nations, Wales has the highest share of 2 km squares with a knotweed record, at 44.7%. Among council areas, 38 have a record in every one of their 2 km squares, and Kirklees has the most records since 2015. Busy recording projects in some areas push their numbers up, so treat rankings as a guide.

Record it with iRecord or the INNS Mapper app, with a photo. Verified records are shared with the NBN Atlas and will appear here when we next update the map.

Use our knotweed identification checker, which asks about what you can see in the current season and compares your plant with the nine plants most often mistaken for knotweed.