Japanese Knotweed: the liability of landowners
Japanese knotweed blights property owners wherever it grows. First brought to Holland by a German botanist, the Royal Botanic Gardens acquired a specimen by 1850 and it was widely used as an ornamental plant. The plant, however, is invasive and destructive, threatening properties up to seven metres away and smothering other plants. It can force its way into concrete foundations and walls, causing serious structural damage.
Buyers now commonly ask about the presence of Japanese Knotweed on land. Its presence can make it harder to sell, mortgage and insure a property, and where a sale is agreed, the landowner will be expected to provide an eradication plan from a reputable company backed by a guarantee. Eradication usually takes two to four years. It can also be more difficult to sell an unaffected neighbouring property, because the roots can cause damage some distance from the plants and the weed can spread.
Unsurprisingly, the increased awareness of the problem has led to an increase in litigation against landowners who fail to control Japanese Knotweed. This should concern all homeowners but will be a particular worry to estate owners, who must take care both to prevent the spread of the weed outside estate boundaries and to ensure that encroaching neighbours and fly-tippers do not allow an infestation to spread onto their land. The plants are controlled waste and unscrupulous traders can be tempted to avoid disposing properly of them.
This summer, the Court of Appeal ruled on cases brought against Network Rail, which had failed to control Japanese Knotweed on its embankments. The case confirmed that a landowner cannot sue a neighbour, on whose property Japanese Knotweed is present, for any reduction in the value of his land, though he may claim for repair and treatment costs where the weed has actually spread. However, even where it has not caused damage to the landowner’s property, he may still seek an injunction requiring the neighbour to tackle the problem and claim compensation for the interference with the amenity value of his land.
Landowners should take note of this decision when considering how to address a Japanese Knotweed problem. Owners of neighbouring properties now have a powerful weapon in their arsenal and need not wait for damage to occur to their properties. It will always be better for landowners to tackle the problem with the help of professionals, rather than risk a costly dispute.
Miles Coates is a solicitor in the Property department at Barker Gotelee Solicitors in Suffolk.
This article previously appeared in County Life, 13th October 2018