Most of us look forward to the re-emergence of the green shoots of spring, but there is one plant whose bright red and green shoots are not so welcome: Japanese Knotweed “Fallopia japonica”.

There has been a lot written in recent press concerning this invasive non-native species, which grows via rhizomes with alarming vigour from April through to October. European legislation came into force at the beginning of January 2015 (European Invasive Alien Species Regulation 2014) obliging member states to control and manage invasive alien species in the European Union. Japanese Knotweed is classed in the same bracket as the grey squirrel, the mitten crab, wild boar and the signal crayfish, all of which could result in a fine or imprisonment for introduction, keeping, sale or release into the wild.  

Knotweed & Properties

The presence of knotweed at a property can potentially have a number of significant consequences.  While some commentators have stated that the practical threat is over-exaggerated, the legal implications are real. Local authorities have the power under s215 Town and Country Planning Act 1990 to require landowners to remedy the condition of land, and failure to comply can result in prosecution, a fine and the costs of undertaking the necessary works. Local authorities or the police can also potentially serve community protection notices under the Anti-Social Behaviour Crime and Policing Act 2014 for failure to keep an alien plant under control. In addition to criminal liability under the Wildlife and Countryside Act 1981 for allowing a release or escape, knotweed is also likely to be classed as controlled waste during the removal process, with associated liability for breach of procedures.

For all these reasons, the presence of knotweed can lower the real or perceived value, insurability and marketability of commercial (and residential) property. It is not yet a general exclusion for lending institutions, although there has been a reported reluctance to lend against affected properties. Certainly, it is not an insured risk on many building insurance policies.  Nevertheless, knotweed need not be a blight on the property and many in the property industry are adopting a balanced and pragmatic approach.

Practical Steps

  • Pre-contract enquiries should address the issue. Standard CPSEs ask about general infestations and hazardous or contaminative substances, as well as environmental problems, but if you are in any doubt, ask the question specifically. Be aware that a standard desktop environmental search will not reveal the presence of a plant species such as knotweed and a survey and assessment will be needed.
  • If you are selling, and the purchaser asks about knotweed, be careful how you respond. There is a risk of being held liable for misrepresentation if you state ‘not as far as the Seller is aware’ without confirming the position in practice. Better to ask the purchaser to make their own inspection, or state that you have not inspected since a certain date and can give no warranty.
  • If you are the owner of a property where knotweed is present, check that any removal works are carried out by specialists and backed by guarantee, which can be assigned to a subsequent purchaser. Ideally, this will also carry insurance if the original company ceases to trade. The Environment Agency has issued guidance and a code of practice on removal.
  • If you are a prospective tenant of a property where knotweed is an issue, consider amending the repair covenant and the service charge provisions to exclude damage caused by the weed, instead making this the landlord’s responsibility. You may also wish to include an obligation on the landlord to comply with statutes concerning the management of knotweed, plus an indemnity for any liability arising from the cost of compliance with statutory notices or for nuisance if the knotweed spreads.

Eleanor Rattay is a solicitor in the Commercial Property Department. If you would like to discuss knotweed or any commercial property issue then please contact her on 0116 289 7000 or by email at

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