Weeds and Japanese knotweed
Read more about our treatment of roadside weeds, Japanese knotweed (an invasive, non-native plant) and on injurious (harmful) weeds.
Footpaths and roadside channels are treated with herbicide between the months of April to September, to eradicate street weeds. Please note that this can be affected and delayed by poor weather conditions. If after 20 working days following the application, weeds are still flourishing, the area will be retreated within 5 working days.
Japanese knotweed was introduced in the UK in the 19th Century from Japan as an ornamental plant. Since being introduced it has spread aggressively throughout the UK, largely unchecked due to a lack of natural predators. This herbaceous perennial grows to approximately 2 metres tall and has an extensive system of rhizomes (roots). It is mainly found in urban areas, by watercourses and waste ground, and is extremely vigorous, causing damage to buildings, river/canal banks and hard surfaces. The plant spreads rapidly and can be spread with a very small section of root/rhizome, stem or crown.
It is difficult and expensive to control. Chemical treatment with a herbicide is the most effective method, but this requires more than one application and there is no guarantee that the plant will be completely killed (the root can remain viable and dormant for possibly as long as 20 years according to the Environment Agency).
Identify Japanese Knotweed
This guide can help identify Japanese knotweed.
- Environmental - Japanese knotweed in not native to the UK. It reduces biodiversity by shading out other species.
- Health and social impact - there are no health impacts associated with Japanese knotweed. Social impacts generally involve disputes over control, damage to property or loss of land
- Economic - Japanese knotweed causes damage to buildings, roads, and river and canal banks, plus the cost of disposal. Eradicating it from construction sites can cost well over £1,000 per square metre as the soil containing it is considered ‘contaminated waste’. When you have treated weeds, the soil contaminated with persistent chemicals, such as herbicides that do not break down, may be a hazardous waste.
Research has found that whilst knotweed is capable of damaging buildings, this tends to occur due to an existing weakness or defect (study by Aecom and the University of Leeds).
It is not an offence to have Japanese knotweed on your land and there is no legal requirement to control it if it remains on your own land, however, the following legal issues apply:
- Under the Wildlife and Countryside Act 1981 it is a criminal offence to plant or otherwise cause Japanese knotweed (or any other non-native plant species) to grow in the wild.
- Under the Environmental Protection Act 1990 any soil or plant material contaminated with Japanese knotweed is classified as controlled waste, with associated offences for importing, producing, carrying, keeping, treating and disposing incorrectly.
- The Control of Pesticides Regulations 1986 covers the precautions necessary when treating Japanese knotweed.
- Allowing Japanese knotweed to grow onto other properties from your land may be regarded as private nuisance under common law (see below).
- The burning of Japanese knotweed may only be done at the site where it grows and may need to be registered with the Environment Agency.
Offences under the Wildlife and Countryside Act 1981 are normally investigated and enforced by the police (wildlife crime officers) and Crown Prosecution Service (wildlife coordinators).
The Environment Agency can provide advice on how to dispose of waste containing non-native plant species, or on treatment near water. You can report waste producers to them who are passing Japanese knotweed to waste carriers without telling them what it is.
If Japanese knotweed is growing on land next to your own and encroaching you may he able to take action for nuisance. It may help to look at the court case of Network Rail Infrastructure Limited v. Williams & Waistell  and we would advise you to seek the advice of a solicitor. In this case, Japanese knotweed from the cutting encroached on the land of Williams and the land of Waistell. After unsuccessful attempts to eradicate the problem, the claimants brought a private nuisance action against Network Rail. Network Rail was aware of the risk of damage and loss of amenity to adjoining properties caused by the proximity of the knotweed and it failed to reasonably prevent the interference with the claimants' enjoyment of their properties.
The Court of Appeal's decision confirms that landowners must take reasonable steps to prevent or minimise encroachment of Japanese knotweed on adjoining land. Landowners need to consider what steps to take to address Japanese knotweed on their land and decide whether active steps are required to prevent rhizomes extending under the boundary fence.
The Council's responsibilities
As a landowner the Council is responsible for treating Japanese knotweed on its own land and for preventing it spreading. We are not responsible for dealing with weeds, including invasive weeds such as Japanese knotweed, on other organisations' land or on domestic properties. We treat knotweed on our land as part of annual spraying programme. We will continue to treat any re-growth of knotweed until the roots have been killed. This can take several years.
Advice for landowners with Japanese knotweed
Please see the Government's advice on preventing the spread of Japanese knotweed.
The best way to treat Japanese knotweed is to spray the foliage with a glyphosate-based weed killer. Burning the shoots with a weed burner will not kill the roots. Many weed killers bought in DIY stores and garden centres contain glyphosate. You must only use approved herbicides. Always follow the instruction on the product and ensure any foliage is well sprayed. Continue to spray emergence of foliage throughout the year.
There are private companies which can contracted to treat your knotweed. Details are available through an internet search.
Remember that Japanese knotweed can lay dormant in the soil for several years. It is best to avoid disturbing the land where it grew and was treated for a few years. If you disturb the area then the plant my re-activate. Ensure you wash and disinfectant any tools used to dig in the area. If the plant re-emerges continue to spray with weed killer.
In winter the plants stems will go brown. At this time of year you can cut the stems off. It is best to do this in February to make sure all stems are dead. You can either burn the stems or wrap them in thick polythene to rot down. Do not allow any part of the stem to touch the soil as it can regrow if it is not totally dead. Where material has been burnt spread the ashes back on the area of land affected by knotweed. This ensures that if any viable material remains you are not spreading the plant.
Before burying non-native invasive plants on your land, check with the Environment Agency to see if this is allowed.
Get permission from the Environment Agency if the plants you intend to treat are near water.
Do not place any part of the plant dead or alive in your garden waste bin, your general waste bin or in a compost heap.
Do not take non-native invasive plant material, dead or alive, to a Household Waste & Recycling Site.
The Weeds Act 1959
The Weeds Act 1959 allows the Secretary of State for Environment, Food and Rural Affairs to take statutory action to control the spread of the following five injurious (harmful) weeds:
- Common ragwort
- Spear thistle
- Creeping or field thistle
- Curled dock
- Broad leaved dock
The Act does not make it illegal to allow the five weeds to grow and responsibility for weed control rests primarily with the occupier of the land on which the weeds are growing. Under the Act, the Secretary of State (acting through Natural England) may serve a notice on an occupier of any land on which the injurious weeds are growing, requiring the occupier to take action to prevent the weeds from spreading.
Further information and reporting
For all queries about weeds on highways and to report Japanese knotweed on council land, phone 0191 278 7878 and ask for ‘Envirocall’.
Please do not contact us to report Japanese knotweed on private land or land owned by other organisations as we are unable to treat it, collect or dispose of it.