A RECENT case has flagged up the problems Japanese knotweed can cause and how expensive it can become if you ignore it.

A long-running argument between neighbouring landowners in Cornwall, Mr Smith and Mrs Line, has resulted in Mrs Line being ordered to pay for the cost of eradicating the weed, which it is expected will take five years.

Mr Smith claimed the knotweed had reduced the value of his beachside family home and that Mrs Line had failed to take the problem seriously.

Japanese knotweed is an invasive and aggressive plant which can damage property, drains, drives and roads. It dies back to ground level during the winter months but then bamboo-like stems emerge and can reach more than 2.1m (7ft), suppressing all other plant growth. Eradication requires specialist intervention and cannot be done successfully without such help.

Because it can spread so quickly, the owner of the land has a legal duty to deal with it. While it is not illegal to have knotweed on your land, it is against the law to allow it to spread.

If you are selling a house you have to say whether or not you have Japanese knotweed in the Property Information Form, therefore you need to be aware if this is an issue for you.

If you do you have knotweed, you must have a management plan. It may be possible to obtain a knotweed indemnity policy which could cover the costs of eradication and legal costs in defending such a claim. Speak to your solicitor about this.

As Mrs Line was also ordered to pay Mr Smith’s legal costs, which will no doubt be substantial, as well as the cost of eradication, this will prove to be a very expensive problem for her. Ignore knotweed at your peril!