Japanese Knotweed


What is Japanese Knotweed?

Reynoutria japonica, also known as, Fallopia japonica and Polygonum Cuspidatum, is a large species of herbaceous perennial plant of the knotweed and buckwheat family Polygonaceae. It is commonly known as Asian knotweed or Japanese knotweed and is native to East Asia in Japan, China and Korea

Japanese knotweed is a highly invasive weed that can grow up to 20cm per day up to height of 4 metres.  Its roots can burrow 3 metres deep and spread up to 7 metres horizontally. Due to its rapid growth, it can cause structural damage by creeping into bricks, cavity walls and building structures as well as suppressing all other plant growth.

Knotweed can spread to adjoining land from nearby land and is particularly prevalent on railway embankments.  It is perhaps therefore unsurprising that the leading case on knotweed involved Network Rail.

Eradication requires determination as it is very hard to remove by hand or eradicate with chemicals. New legislation now covers its control

It is important to understand that:

  • If you are selling, it is your responsibility to check the garden for Japanese knotweed (bearing in mind that it can die back in winter). The TA6 form asks you to confirm whether your property is affected by Japanese knotweed and, where it is, to provide a management plan for its eradication from a professional company (see Seeking Help from the Professionals below)
  • If you are buying, the presence of Japanese knotweed will be stated in the responses to the TA6 form. This often results in your mortgage lender requiring assurances that it will be eradicated before agreeing the funds. A management plan by a professional eradication company, backed by a transferable guarantee, is usually sufficient. It is most common for this plan to be provided by the seller before the purchase is completed
  • Whether a buyer or seller, it is also worth being pro-active and checking the property for Japanese knotweed. Disputes over the identity of a plant, the failure to disclose its presence, or the lack of a management plan can result in delays, increased costs later in the buying process, or even a possible misrepresentation claim after the sale, so this approach will help avoid problems
  • Working with expert knotweed specialists, we are able to assist homeowners in identifying when and how knotweed spread to their property and, in appropriate cases, we can assist them by bringing claims against those responsible.