The problem of knotweed

One of the first documents sent to a property seller by their conveyancing solicitor is the Property Information Form. This is a form, completed by the seller, which provides a lot of practical information about the property for the buyer. It includes such issues as boundaries, disputes, planning, occupiers, utilities and environmental matters such as Japanese knotweed.

Japanese knotweed is a weed that spreads rapidly. The difficulty for sellers and buyers is the fact that in winter the plant dies back to ground level but by early summer the bamboo -like stems emerge from rhizomes deep underground. These can extend to over 2m and suppress all other plant growth. 

Japanese knotweed is difficult to remove by hand or eradicate with chemicals. It usually requires specialist treatment over a long period of time to remove the threat.  It is not illegal to have Japanese knotweed in a garden but the property owner should aim to control the plant to prevent it becoming a problem. We have reported in earlier newsletters on recent cases which have imposed liability on property owners for failing to deal effectively with Japanese knotweed resulting in a decrease in value of neighbouring property.

The harsh reality is that a property affected by Japanese knotweed may be difficult to sell or to mortgage.

The Property Information Form has recently been updated and the Law Society's guidance notes contain much more information about Japanese knotweed and its risks. A property seller is asked whether the property is affected by Japanese knotweed. The guidance states that if 'no' is chosen as the answer, the seller must be certain that no root is present in the ground of the property, or within 3m of the property boundary even if there are no visible signs above ground. Sellers are reminded that even if no above ground knotweed growth is visible, they should not assume that physical excavation or remediation of the root has or will result in complete eradication.

The stringent approach to this guidance means that sellers are likely to state 'not known', rather than an absolute 'no' when dealing with the question on Japanese knotweed. If a seller states that they do not know whether the property is affected, this effectively means that buyers must carry out investigations of their own and even consider commissioning a professional knotweed survey prior to exchange of contracts.

Any property buyer must take care, particularly when buying in the winter months when Japanese knotweed will not be visible.

To discuss this or any other property related matter, contact us.