Japanese knotweed ‘hotspots’ in Hampshire revealed, with New Forest in top 10

The New Forest has been named among the top Japanese knotweed ‘hotspots’ in Hampshire.

Invasive specialist Environet has produced the list and a heatmap using the latest data from its online tracker.

There have been a total of 633 verified knotweed sightings in Hampshire, or 0.43 incidences in every square mile with Southampton having the most.

People can check their area by inputting their postcode into the online map to discover how many sightings of the plant has been recorded in that area. They can also input information about any they discover.

Japanese knotweed first arrived in UK in Victorian times and since then has spread extensively. It can damage pathways, drains and cavity walls.

If you suspect you have knotweed on or near your property, email a photo to expert@environetuk.com and have it identified for free.

To check your area visit: environetuk.com/exposed-japanese-knotweed-heat-map

Hampshire’s Top 10 Japanese knotweed hotspots for 2025, and number of instances

1. Southampton 93

2. Portsmouth 34

3. Winchester 27

4. Fleet 26

5. Southsea 22

6. Andover 20

7. New Forest National Park 18

=8. Basingstoke 17

=8. Eastleigh 17

10. Petersfield 16