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Japanese knotweed can grow up to 10 cm per day during peak growing season and can reach heights of 3-4 metres. It has a robust rhizome system that can remain dormant and viable for many years.
Primarily through root and stem fragments. Even small pieces can regrow into a new plant, making it difficult to control once established.
Japanese knotweed becomes a property issue when it affects lending, development, saleability, neighbour relations or future land use.
In practice, the biggest risks usually involve:
Professional surveys, clear disclosure and appropriate remediation strategies are normally enough to manage these risks effectively.
Further guidance:
There is no single “best” method for removing Japanese knotweed. The correct approach depends on:
Common remediation approaches include:
On development sites, excavation-based approaches are often preferred because they align better with construction programmes and reduce long-term liability.
Further guidance:
Japanese knotweed is widespread across the UK, with notable hotspots. Various online maps and postcode checkers are available to see if your area is affected.
Check local authority websites and environmental agencies for information on local infestations and reporting procedures.
| Situation | Recommended guidance |
|---|---|
| Buying a property | Buying guide |
| Selling a property | Selling guide |
| Mortgage concerns | Lenders guide |
| Development land | Developers guide |
| Neighbour disputes | Neighbours guide |
| Housing associations | Housing associations guide |
| Commercial remediation | Commercial removal |
| Disposal obligations | Disposal guide |
| Survey and valuation issues | Surveyors guide |
| Legal liability | Legal guide |
The aggressive nature of the plants, and ability to survive in unfavourable conditions mean that they can cause damage to the built environment too. We often see cases of damage to hard surfaces such as patios, asphalt and drains. Although it is a myth that knotweed can grow through solid concrete, it certainly has no problem exploiting the smallest of gaps and weaknesses, eventually causing real damage. For further information on the type of damage knotweed can cause, check out our short video or read more.
In certain circumstances, it can stop you from getting a mortgage. This is usually the case if the knotweed has become so invasive that it has damaged the infrastructure of the building and walls themselves. In most cases, as long as you have a management plan in place, there shouldn’t be a problem.
Read our full guide to Japanese knotweed and mortgages here.
Having Japanese knotweed on your property is not against the law, but you must stop it from spreading into the wild, or to your neighbours. You must also be honest when it comes to selling property affected by knotweed and declare it to any potential buyer, even if you think the problem is sorted.
Read our full guide to Japanese knotweed and the law here.
Local councils and the Environment Agency will not be able to help if Japanese knotweed is on private land. But rest assured, where Japanese knotweed is identified at an early stage and tackled correctly, problems can usually be avoided. Our specialist consultants complete thorough surveys to identify the extent of the problem. Our plans aren’t one-size-fits-all; they’re customised to tackle the invasive species at your property effectively, taking account of all of your requirements.
Our team of experts is available between 9am and 5:30pm, Monday to Friday to answer your enquiries and advise you on the next steps
Want a survey?
If you already know you have an invasive plant problem, you can request a survey online in less than two minutes by providing a few brief details. A member of the team will swiftly come back to you with further information and our availability.
Need quick plant identification?
Simply upload a few images of your problem plant to our identification form and one of our invasive plant experts will take a look and let you know, free of charge what you are dealing with. We’ll also be there to help with next steps where necessary.
