Britain’s invasive weed hotspots as councils record almost 7,900 complaints
Britain’s councils received 7,899 complaints about Japanese knotweed, Giant hogweed, bamboo and Himalayan balsam over the past five years, with knotweed accounting for almost three quarters of the total.
From damaged gardens and property worries to disputes between neighbours, the latest figures reveal the areas of Britain bearing the brunt of the problem.
New analysis of council data obtained through Freedom of Information requests by invasive weed removal specialists Environment Controls has revealed that Cornwall is Britain’s biggest invasive weed hotspot, with 633 complaints recorded since 2021.
Surrey follows with 546, while North Lanarkshire recorded 517.
Nationally, complaints reached a five-year high in 2024, when councils logged 2,028 cases.
Japanese knotweed was by far the most commonly reported invasive plant in the dataset, accounting for 5,755 complaints over the five-year period, equivalent to 73% of all complaints.
Not only does Cornwall have the highest number of invasive weed complaints, it is also the UK’s Japanese knotweed hotspot, with 552 individual cases.
That is 237 more than Argyll and Bute, which recorded 315, and 257 more than North Lanarkshire, which came in third with 295.
The figures highlight that invasive weeds are not confined to one corner of the country, with councils recording complaints from the south of England to Scotland.
Despite Japanese knotweed accounting for the vast majority of complaints, other invasive plants are also creating problems for homeowners.
Giant hogweed resulted in 1,382 complaints, making it the second most commonly reported invasive plant in the dataset.
But the plant presents a very different concern for homeowners, as contact with Giant hogweed can pose a serious health risk.
Its sap can cause painful blistering and skin inflammation, with affected skin becoming extremely sensitive to sunlight.
North Lanarkshire recorded the highest number of Giant hogweed complaints, with 222, followed by Gloucestershire with 125, and Fife with 121.
Bamboo accounted for a further 490 complaints during the five-year period, with Surrey emerging as the UK’s bamboo hotspot after logging 174 cases.
While bamboo may look harmless, fast-spreading varieties can become a headache when they creep across property boundaries.
Cornwall also recorded the highest number of complaints about Himalayan balsam, with 43 cases. Argyll and Bute and Cheltenham both recorded 35, putting them joint second.
Meanwhile, Himalayan balsam accounted for just 3% of claims with 272 nationally.
Taken together, the figures suggest that different invasive plants are creating different hotspots across the country, rather than one type of weed being concentrated in the same areas.
Top 10 UK Councils with the most invasive weed complaints since 2021:
Cornwall Council Complaints: 633
Surrey County Council Complaints: 546
North Lanarkshire Council Complaints: 517
Argyll and Bute Council Complaints: 357
Gloucestershire County Council Complaints: 281
Kent County Council Complaints: 268
Merthyr Tydfil County Borough Council Complaints: 257
Rochdale Metropolitan Borough Council Complaints: 243
Torfaen County Borough Council Complaints: 242
Bromley Borough Council Complaints: 196
Jennifer Holmes from Environment Controls said: “Seeing such high volumes of Giant hogweed complaints in North Lanarkshire is alarming, as even brief contact with the plant can lead to painful blistering that reoccurs when the skin is exposed to sunlight.
“Homeowners should never cut, dig up or handle a plant they suspect may be Giant hogweed. If you think you have found it, keep children and pets away from the area and arrange for it to be identified by a suitably qualified professional.”
With invasive plants potentially affecting gardens and property boundaries, Environment Controls urges homeowners to take care when dealing with unfamiliar plants, particularly where Japanese knotweed or Giant hogweed is suspected, and Holmes also recommends learning how to identify other harmful plants such as Hemlock and Horsetail by visiting the website’s Invasive Plants Directory.
Five tips for homeowners who suspect their neighbours have invasive weeds:
Don't cut or dig up an unidentified invasive plant. Attempting to remove some species without knowing what they are can cause them to spread further.
Take a photograph instead. Homeowners unsure what they have growing in their garden can use Environment Controls' free identification service to seek expert advice.
Keep children and pets away from Giant hogweed. Contact with its sap can cause painful skin reactions that can be aggravated by sunlight.
Check plants growing close to property boundaries. Fast-spreading species such as bamboo can spread through underground rhizomes into neighbouring gardens.
Speak to your neighbour if a plant is spreading from adjoining land. If the issue cannot be resolved, homeowners can contact their local council's environmental health or neighbourhood enforcement team.
An invasive plant does not necessarily have to be growing in your own garden to become a problem. Where a plant is spreading from neighbouring land, homeowners may be able to raise the issue with their local council.
Where appropriate, councils may investigate complaints about invasive plants and, depending on the circumstances, could issue a Community Protection Notice requiring a landowner to take reasonable steps to control a problem.
Failing to comply with a Community Protection Notice is an offence. A fixed penalty notice of up to £100 may be issued, while a breach dealt with in court can result in a fine of up to £2,500 for an individual. Enforcement powers and procedures vary between councils.
Jennifer Holmes added: “Early identification is important because different plants require different treatment methods. Trying to remove an invasive weed without understanding what it is can make the problem worse, increase the risk of spreading it and, in the case of Giant hogweed, create a serious health hazard.
“Environment Controls is committed to helping homeowners, councils and landowners manage invasive plants in a practical and environmentally responsible way.”
The data suggests that invasive weeds are not simply a problem for homeowners who already have them in their gardens. If a plant is spreading from a neighbouring property, spotting it early could help homeowners get on top of the issue before it crosses the boundary.
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