Beware the knotweed

When you are buying or selling a property you should consider whether there is  the possible existence or history of the invasive plant “Japanese Knotweed” and whether measures of remediation are being enforced on the property.

Japanese Knotweed is an invasive plant and is notorious for its damaging buildings and public works should it make an appearance.

If measures are not taken to control and eradicate the weed, extensive damage can be caused to underground pipe work, drainage systems and foundations due to the spread of the weed through underground stems and stem segments.

Pathways, driveways, walls, outbuildings, conservatories and gardens may also suffer should the Japanese Kotweed increase in size.

If your survey report reveals the presence of Japanese Knotweed your solicitor will check with your mortgage lender as to their requirements.

In these circumstances, there is no blanket policy in place and mortgage lenders will consider the matter on a case by case basis.

Adjacent or adjoining properties may also need to be checked for presence of the weed as the stems can expand over a large area underground, therefore spreading through the soil to breach other properties.

Advice from the Environment Agency is to cooperate with neighbouring landowners so as to resolve the problem amicably and avoid legal action.

It is very important to consider the range of harm this invasive plant can cause before considering buying a property, as well as the time period and expense required to eradicate it as s very difficult to remove.

Therefore, it is important to ensure that a reliable consultant is employed to eradicate it.

The actual process of remediation should be expected to last four years at the very least.

Removal techniques have varied in success in the past and usually involve a combination of physical removal such as excavation and cutting, and chemical removal through the use of herbicides.

Herbicide treatment is effective over a long period of time and may have to be applied for at more than three years before the weed stops growing back.

When looking into buying a property with a historical or current presence of Japanese Knotweed, prospective buyers should enquire with regard to the previous methods of eradication used or the active measures in process at the time of enquiry.

This is particularly important if there is a history of Japanese Knotweed surrounding the property as the stem segments can stay dormant for 20 years before becoming active again.

Once the Japanese Knotweed has been removed, the remediation processes should all be documented so as to reassure future buyers of the success of the eradication, thus avoiding complications during the sale of the property.

Your solicitor should be able to advise you of the procedure to follow if you are buying a property where your survey report has revealed the presence of this invasive plant.

* For more information on the issues raised by this article, please contact Claire Simmons.