Exposed™: The Japanese Knotweed Heatmap is an interactive online heatmap of Japanese knotweed sightings across the UK. Designed to inform homeowners and homebuyers of the local presence of knotweed and the potential risk to their property, the data is generated from over 50,000 known infestations, with new sightings added daily.

What does Japanese Knotweed look like?

New red shoot appears in spring resembling asparagus

Distinctive shield shaped leaves with alternating sub-branches

Clusters of attractive white flowers in summer

In winter the yellowy orange leaves will eventually turn brown

See our Identification page

Is your property affected by Japanese knotweed?

Here are the top 6 reasons why Japanese knotweed should be removed from residential property:

  1. Protect your Assets - Knotweed will make it more difficult to sell an affected property, impacting its value by an average of 10%. Half of would-be buyers will walk away from a property known to be infested with knotweed. Sellers are required by law to disclose the presence of knotweed – if they don’t, they risk an expensive misrepresentation claim in the courts.
  2. A Growing Problem - Knotweed is programmed to grow, its underground rhizome system extending year on year, infecting more ground. It’s a problem that simply won’t go away on its own, so the sooner it’s tackled the better.
  3. Nuisance Neighbours - Knotweed does not respect property boundaries and those who allow it to spread also diminish the value of their neighbour’s property. This can lead to neighbour disputes and costly civil claims under private nuisance legislation.
  4. Damage - Knotweed can and does cause damage to property. Perhaps not as bad as some might make you believe, but don’t under-estimate the damage the plant can wreak.
  5. DIY Disasters - Knotweed and building or landscaping projects don't mix! If you want to add that conservatory, summer house or home office pod to the garden, tackle the Japanese knotweed first. 
  6. The Heavy Hand of the Law -  And for those who are still not convinced, be aware that an injunction or Community Protection Notice, otherwise known as an ASBO, can enforce people to act to remove knotweed from their property

Whilst it’s not illegal to have knotweed on your property, there are compelling reasons to act. Do the responsible thing and get it removed, protect the value of your home and avoid neighbour disputes.

Want to know how?


Heatmap Details

Learn More about how we Built it and How it Helps

This tool is an invaluable source of information to property professionals involved in transactions such as chartered surveyors, conveyancing solicitors and estate agents. Where a high number of knotweed sightings appear nearby, homebuyers may wish to instruct a Japanese knotweed survey to check the likelihood of the property they intend to buy being affected or at risk of encroachment from infestations in the vicinity.

Report Sightings – Join the Fight Against Japanese Knotweed

You can join the fight against Japanese knotweed by reporting any sightings of Japanese knotweed online, using your smartphone, tablet, or desktop computer. We’ve made it really simple, it takes just a few seconds. Click “Add Sighting”, zoom in on the satellite view and click the central position of the knotweed location. You’ll only be asked to define the size of the infestation, some further information is requested but is optional. No sign-in or passwords are required.

Wherever possible we’ll verify new sighting reports to keep the Heatmap both current and accurate.

japanese knotweed uk map

Exposed, the Japanese Knotweed Heatmap

Our Regional Director explains how our popular Heatmap works.

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