Japanese knotweed is a perennial plant that spreads rapidly by its roots and stems and is extremely difficult to eradicate. Between April and October it can grow up to 10cm a day, the roots can extend to a depth of three metres and seven metres laterally. It can be costly to treat and damaging to the area it invades. Even if treated, if a small strand of root is left in the ground, the plant can grow back into the land. It is therefore extremely important to establish whether or not the property you are purchasing is at all affected by Japanese knotweed.
As part of the standard pre-contract enquiries raised with the seller of a property, a specific enquiry is raised as part of the Property Information Form asking whether there is knotweed on the property and, if so, whether there is a management plan in place to control it. Of course, it is possible that a property may be affected by the plant, but the seller does not know (especially if, for example, a seller has not lived at the property – if it has been let out or vacant for some time). It is therefore very important that you carry out your own inspection of the property and arrange for a surveyor to inspect the property to confirm whether or not there is any Japanese knotweed on the property or the immediate surrounding area. If knotweed is discovered, you will want to make enquiries with the seller to ensure that a treatment plan is in place or that one is put in place immediately. If you are purchasing with a mortgage, your mortgage lender may also need to be informed of the presence of the plant.
For further information please see the following link: https://www.gov.uk/prevent-the-spread-of-harmful-invasive-and-non-native-plants.