Our Japanese Knotweed Map

Tracking the Spread Across the UK

Our interactive Japanese Knotweed heatmap provides a visual representation of confirmed infestations we’ve treated over the past three years.

This powerful visualisation tool uses colour intensity to show concentration levels of Japanese Knotweed across different regions, with darker areas indicating higher numbers of infestations.

By examining this data, property owners, developers, and local authorities can clearly see that this invasive species isn’t isolated to a few problem areas but is prevalent throughout the UK.

Understanding the distribution pattern helps raise awareness about the widespread nature of this issue and underscores the importance of professional identification and treatment services to combat this resilient plant before it spreads further in your area.

Japanese knotweed infestations are becoming an epidemic across the UK, this invasive species can devalue your property and cause structural damage to buildings, paving and drainage systems. Knowing where Japanese knotweed grows and if it is near your property has never been more important for homeowners, property developers and local authorities.

This guide will show you how to use our interactive knotweed heatmap to check your UK postcode, see concentration patterns in your area and get professional treatment services.

The Current Situation

Japanese knotweed (Fallopia japonica) was originally imported to Britain from Japan in the nineteenth century as an ornamental plant. Its bamboo-like stems and heart-shaped leaves made it a popular choice for Victorian gardens. But what the Victorians didn’t realise was its ability to spread rapidly and cause massive damage to infrastructure. It was also brought in to stabilise and beautify railway embankments, which helped it spread across the country.

Today Japanese knotweed isn’t limited to a few problem areas but is widespread across the UK, including many areas in England. Our treatment data shows concerning patterns of growth across multiple regions.

Urban centres and former industrial areas
Transport corridors, especially railway embankments
Waterways and riparian zones
New build residential areas
Areas with high construction activity

Beyond direct property devaluation, mortgage lenders often require specialist treatment programmes and insurance backed guarantees before they will approve a loan on a property affected by knotweed. Legal cases regarding knotweed have increased by 25% in the last few years with neighbours bringing claims against those who allow the plant to spread to adjacent properties.

The Impact

Japanese knotweed can have a big impact on residential property. The underground rhizome can damage foundations, walls and other structures and cost thousands to repair. Japanese knotweed can also reduce property value and make a property hard to sell. And it can lead to neighbour disputes and community protection notices.

Professional help is key to treating Japanese knotweed and a Japanese knotweed survey will give you an accurate picture of the situation. By understanding the impact of Japanese knotweed you can protect your property and prevent the spread of this invasive plant.

Japanese Knotweed Checker: Find Invasive Plants by Postcode

Our interactive Japanese knotweed heatmap shows confirmed knotweed projects we’ve treated over the past three years. This tool allows you to quickly check the risk level in your area with a simple postcode search. It’s updated with recorded cases of Japanese knotweed so you have the most up to date information.

Here’s how to use our Japanese knotweed postcode check tool:

Go to the heatmap section above
Enter your full postcode in the search field
View the colour coded results showing knotweed concentration in your area

The colours show the concentration of Japanese knotweed in different areas, with darker areas having more infestations. This visualisation will show you which areas need more attention and potentially a survey.

Our map is updated as we complete new treatments across the UK. As we treat new areas, this information is added to the system so you have the latest data on knotweed distribution in your area.

Japanese Knotweed Hotspots UK: Where it’s Most Common

Our treatment data shows several patterns in knotweed distribution across the UK. While Japanese knotweed can be found everywhere in Britain, some areas are Japanese knotweed hotspots, with higher concentrations. It shows live cases of Japanese knotweed treatments that are on going and growth trends over the past 3 years.

Our treatment records show highest levels of infestation in:

South Wales and the Valleys This area has the highest concentration of Japanese knotweed in the UK. The combination of former industrial land, connected waterways and railway networks has created perfect conditions for knotweed to spread. Areas around Cardiff, Swansea and the valleys are particularly bad. Bristol has the most cases in the UK, 13 per square mile.

Greater London and the Home Counties London’s urban sprawl has provided many pathways for knotweed to spread. Our treatment data shows clusters of affected property around major infrastructure projects, waterways like the Thames and its tributaries and areas of Victorian development where the plant was first introduced. Hotspots include parts of East London, the Thames Valley and areas of rapid development. London has 5.93 cases of Japanese knotweed per square mile.

The North West Liverpool, Manchester and surrounding urban areas have higher levels of knotweed, particularly in areas of regeneration or former industrial land. The canal network in this area has allowed it to spread far and wide. Merseyside has 6.45 cases of Japanese knotweed per square mile.

Urban vs Rural Distribution Our treatment history shows a clear trend: Japanese knotweed can grow in rural areas but urban and peri-urban areas have much higher concentrations. This seems to be linked to:

More soil disturbance
More movement of contaminated soil during construction
More transport networks to spread it
Historical industrial activities that unknowingly spread rhizome fragments

The presence of knotweed near ports like Bristol and Liverpool is also linked to historical shipping that brought the plant to the UK.

Our specialists have found that areas with recent housing developments on former industrial land have particularly high levels of knotweed activity as construction work can spread dormant rhizomes that then thrive in newly landscaped areas.

Japanese Knotweed Area Check

Using our heatmap is a crucial part of the property buying process. Checking for Japanese knotweed before you buy can save you thousands of pounds and stress in the long run.

Here’s how to use our heatmap:

Initial screening: Check any property’s area on our heatmap before viewing
Enhanced due diligence: For medium to high risk areas, ask the seller for specific information on the TA6 property information form
Professional surveys: In high risk areas, commission a knotweed survey instead of a standard building survey
Negotiation leverage: Use evidence of local knotweed to negotiate price reductions or treatment guarantees
Future planning: Understand the management costs if you buy in a high risk area

The heatmap helps property owners, developers and local authorities assess risk in an area before making big decisions. This is especially important given the long term implications of knotweed.

Properties with Japanese knotweed face several issues:

Difficulty getting mortgage finance
Need for specialist insurance products
Disclosure requirements when selling
Legal liability if it spreads to neighbour’s properties
Development restrictions

Around 5% of British homes are affected by Japanese knotweed, either directly or by a neighbour’s property.

Professional Solutions

If our heatmap shows your area is in a high-risk area you need to act fast to protect your property.

The immediate steps to take if you suspect Japanese knotweed on or near your property are:

Document the suspected infestation with photos and notes
Get professional identification through our team
Notify relevant parties including neighbours, mortgage providers and insurers if necessary
Don’t disturb the plant as DIY removal can make it worse
Commission a professional Japanese knotweed survey to identify the extent and origin of the infestation and determine the best treatment options

Our identification service will confirm if the suspected knotweed is present. Our specialists are trained to distinguish Japanese knotweed from similar looking plants like Russian vine, bindweed and Himalayan balsam—a crucial distinction as misidentification can cost you unnecessary treatment costs.

Property owners with Knotweed have specific legal obligations. Under the Wildlife and Countryside Act 1981 and Environmental Protection Act 1990 allowing knotweed to spread from your property is a criminal offence. Recent court cases have also established liability for devaluation of neighbouring homes if you don’t take adequate control measures.

The importance of professional identification and treatment services to stop this invasive plant species before it spreads further in your area cannot be overstated. DIY control methods fail as knotweed has an extensive underground rhizome network which can spread up to 7 metres horizontally and 3 metres vertically from the visible growth. Knotweed is almost impossible to remove by hand or eradicate with chemicals, that’s why professional intervention is needed.

Our treatment protocols use a combination of methods depending on the severity of the infestation:

Herbicide programmes applied at specific growth stages
Screening our ‘Zero to Landfill’ solution includes excavation, screening, separation and relocation of the knotweed on site using our Environment Agency (EA) approved method.
Excavation and root barrier installation for development sites
Stem injection for sensitive areas
Rhizome fragmentation and cultivation for severe Knotweed sightings
Monitoring and follow-up treatments to prevent re-growth

Removing knotweed can cost tens of thousands of pounds so it’s essential to have a tailored and effective treatment plan. With professional help Japanese knotweed can be treated successfully and prevent property damage and devaluation.

Protecting Your Property

Our Japanese knotweed heatmap is a vital tool for property owners. It provides treatment based data on knotweed distribution so you can make informed decisions and act early.

Japanese knotweed is a national problem so no area is knotweed free, although risk levels vary. Professional identification is key as early treatment saves you money and your property.

KNOTWEED REMOVAL AVAILABLE THROUGHOUT:

ENGLAND

Leicestershire
Lincolnshire
Merseyside
Norfolk
Northamptonshire
Northumberland
Nottinghamshire
Oxfordshire
Rutland
Shropshire
Somerset

WALES

Isle of Anglesey (Ynys Môn)
Gwynedd
Conwy
Denbighshire (Sir Ddinbych)
Flintshire (Sir y Fflint)
Wrexham (Wrecsam)

Ceredigion
Powys
Pembrokeshire (Sir Benfro)
Carmarthenshire (Sir Gaerfyrddin)
Swansea (Abertawe)
Neath Port Talbot (Castell-nedd Port Talbot)

Bridgend (Pen-y-bont ar Ogwr)
Vale of Glamorgan (Bro Morgannwg)
Rhondda Cynon Taff
Cardiff (Caerdydd)
Merthyr Tydfil (Merthyr Tudful)
Caerphilly (Caerffili)

Newport (Casnewydd)
Torfaen (Tor-faen)
Blaenau Gwent
Monmouthshire (Sir Fynwy)

SCOTLAND

Aberdeenshire
Angus
Argyll
Ayrshire
Banffshire
Berwickshire
Bute
Caithness
Clackmannanshire

Dumfriesshire
Dunbartonshire
East Lothian
Fife
Inverness-shire
Kincardineshire
Kinross-shire
Kirkcudbrightshire
Lanarkshire

Midlothian
Moray
Nairnshire
Orkney
Peeblesshire
Perthshire
Renfrewshire
Ross and Cromarty
Roxburghshire

Selkirkshire
Shetland
Stirlingshire
Sutherland
West Lothian
Wigtownshire

FAQs

How accurate is the knotweed map for my property?

The heatmap shows concentration levels by area not individual properties. Homeowners who own their own home should consider a professional survey for an accurate assessment as it provides definitive identification.

How often is the knotweed heatmap updated?

Our map is updated quarterly with new treatment data so it reflects current infestation patterns across the UK.

Can Japanese knotweed spread to my property even if it’s not shown on the map?

Yes. The map shows treatments we have carried out not all existing knotweed.

What should I do if my neighbour has Japanese knotweed?

Document the situation, inform your neighbour constructively and suggest professional treatment. If they refuse to address the issue contact us for advice.

Does insurance cover Japanese knotweed treatment?

Standard building insurance doesn’t cover knotweed treatment. Specialist policies are available and our treatment programmes include insurance backed guarantees that meet mortgage lender requirements.

How fast does knotweed spread?

Above ground knotweed can grow up to 10cm per day during peak growing season. Underground rhizomes can extend up to 3 metres annually in suitable conditions.

Will Japanese knotweed damage my house?

While it can’t penetrate solid concrete foundations, knotweed can exploit existing weaknesses in structures, expand cracks, damage drainage systems and grow through cavity walls. If left unchecked Japanese knotweed can cause serious structural issues. Early treatment prevents these serious structural issues.