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Japanese Knotweed – guidance for property owners

02 June 2015

What lurks beneath could cause homebuyers and sellers a headache……

The winter months could hide a very difficult problem for prospective house buyers and sellers in the form of the dreaded and destructive Japanese knotweed plant warns Adams & Remers solicitors.

Japanese knotweed is a tall vigorous and aggressively invasive plant, which was introduced to the UK in the 19th century. During the winter months the leaves of the plant die back to reveal woody stems. In March and April the plant sends up new red/purple coloured shoots and this may be when you first become aware of the problem. The plant can grow up to 40mm per day and the root system can go beyond 2m depth and 7m lateral growth from the parent plant. It can significantly affect the structure of a building.

Suzanne Bowman at Adams & Remers comments: “Japanese knotweed can be such a big problem as people may be unaware it is lurking beneath their or a neighbouring property until the spring when the shoots start to appear. If you are a homeowner, it may make your property unsalable until is has been removed and this is where the problem lies if it isn’t on your land. Most lenders won’t allow a mortgage or a remortgage to be taken out on a property with this problem.”

“Having recently dealt with a property transaction where Japanese knotweed was found to be present, it can be devastating for the homebuyer and home owner and also very costly to remove.”

It is an offence to plant or cause Japanese Knotweed to spread in the wild under the Wildlife and Countryside Act 1981 and all waste containing Japanese knotweed comes under the control of Part II of the Environmental Protection Act 1990.

If you suspect Japanese knotweed is on site you should consult The Environment Agency code of practice (2013) https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/296930/LIT_2695_df1209.pdf for the management, destruction and disposal of Japanese knotweed.


  • If you are buying a new property, ask the builder for a legal guarantee to say there is no Japanese knotweed on the site.
  • If you find Japanese knotweed in your garden, consult an expert on how the site can be treated. They may recommend a combination of methods which may include using herbicides, a bund method to move the knotweed to an area of the site which is not used to help buy time, screening and sieving soil, burying soil, using a root barrier membrane, on site burning of plant materials or off site disposal.
  • If the plant has escaped from a neighbour’s garden into your own, they may be guilty of a Private Nuisance, or equally you may be guilty if it has escaped from your garden into that of your neighbour.
  • You will need to keep evidence that you have informed the person on whose land it has originated about the presence of the knotweed when you first discover it.

Suzanne Bowman continues: “There is a question about Japanese knotweed on the sellers forms and sellers need to be careful when they are completing it as if they do not know, they could be liable for misrepresentation.”

“Finally I would also urge people to use professionals such as surveyors who are fully aware of the problem. I recently had a client whose surveyor had a suspicion that knotweed was present and it cost the homeowner over £600 to remove what turned out to be a fennel plant!”

For further information regarding this issue contact Suzanne Bowman at Adams & Remers.


+44 (0)1273 403220


+44 (0)1273 403220