Japanese Knotweed – the Scourge of the Land

We’ve heard of it as a purchaser.  We’ve heard about it when selling a property.  We’ve heard of it as a property manager.  We’ve heard of it as an estate agent and we’re hearing more and more of it in the legal world.


Japanese Knotwood (Fallopia Japonica) is a highly invasive plant that is becoming increasingly burdensome in urban areas, as it can grow through weaknesses in buildings, construction materials and foundations.  As it spreads rapidly because of its great capacity to propagate, it can cause thousands of pounds worth of damage and therefore action MUST be taken quickly to control it.


Managing this pest is the responsibility of the owner/occupier of the site.  Although there is no statutory requirement to control or eradicate this plant, we’ll explain why you should take action before the onslaught of its tenacious propagation.   Under the Wildlife & Countryside Act 1981 it is an offence to “plant or otherwise cause Japanese Knotweed to grow in the wild“.  This means that disposing of the plant is the dangerous part!  A magistrates’ court can impose a fine of up to £5000 or a imprisonment of up to 6 months if found to be guilty.  A snapshot of the law:

  • You must not cause Japanese Knotweed to grow in the wild.
  • If you have Japanese Knotweed on your property, you must not allow it to spread into neighbouring properties. It would be classed as a private nuisance and you could be prosecuted under civil law, resulting in financial penalties. Private nuisance is defined as “any continuous activity or state of affairs causing a substantial and unreasonable interference with a [claimant’s] land or his use or enjoyment of that land“.

As the presence of Japanese Knotweed has been known to result in the refusal of mortgages on homes up for sale, it is really difficult to ascertain where the source lies if near a boundary, and who the onus is on to pay for safe disposal.


Under Section 33(1)(a) and (1)(b) of the Environmental Protection Act 1990 it is an offence to deposit, treat, keep or dispose of controlled waste without a licence.  Under Section 34 of the same Act – the duty of care is on a person who imports, produces, carries, keep, treats or disposes of controlled waste and their duty. Breach of this duty of care is a criminal offence.  The Environment Agency is responsible for enforcement.

Eco Control Solutions, environmental consultants providing effective Japanese knotweed solutions for the destruction and disposal of this invasive plant, comment “All parts of the plant and any soil contaminated with the rhizome are classified as controlled waste and are required legally to be removed and disposed of by a licensed waste control operator.

There are a few types of removal (physical – using heavy machinery and intrusive work); herbicides (this is more of a control strategy, because pesticides cannot fix the root of the problem – re-spray is important and it usually takes 3 years to treat the plant until the underground rhizomes become dormant); and biological control (controversial but sustainable).


If you are a freeholder, a site owner or a landlord – the onus is on you to ensure that you are compliant in understanding the legislation surrounding this pesky plant. If you are a Property Manager then you must ensure you understand the Sales Information Packs and attach the correct surveys or reports.  The Law states:

If a neighbour allows Japanese Knotweed to encroach onto your property, it may constitute a private nuisance under common law.

If fault is clear, property owners affected by Japanese Knotweed growth from a neighbouring property may be able to apply to court for an injunction requiring the owner of the property to prevent the nuisance.

Such claims can also include a sum of money in damages relating to control, physical damage to property and/or devaluation of property.

Allsquare Law work with Japanese Knotweed specialists, Eco Control Solutions, who can offer site surveys and reports.

If you’re concerned about legalities, our Property Law specialists are at hand to help if you have any queries – for a free, non-obligatory conversation please call our team on 01628 200215 or send us an email here.