Japanese knotweed – a cautionary tale from a recent case

If you have ever been involved in a property transaction whether buying, selling or even acting for clients, you would have heard the whispers of a particular plant name. You guessed it: Japanese knotweed.

An infamous plant

This infamous plant causes no end of headaches for homeowners, solicitors and lenders alike. It has long and deep reaching roots, also known as rhizomes that can cause issues with pipes, drainage and even foundation damage. It is difficult to spot as it looks like a common garden plant. Its main features are asparagus-type shoots in Spring and Summer, it produces heart shaped leaves and white flowers.

The mistake homeowners make when they have this plant in their garden or on their land, is assuming it has gone when it dies off in the winter. The plant on the surface may die but the roots keep growing and come Spring it will pop up again. You might not even know you have it, many homeowners don’t. If the property has Japanese knotweed, it requires professional removal and treatment programs which are costly but necessary. You would be hard pushed to find a lender who would provide a mortgage on a property with an active case of Japanese knotweed.

Case in focus: Downing v Henderson (2023)

In the recent case of Downing v Henderson (2023), upon moving in Mr Downing was tidying up the garden when he discovered knotweed canes behind a bush. He subsequently sued Mr Henderson for failing to disclose the property had a knotweed infestation. Mr Henderson had ticked ‘no’ to the question on the Property Information Form (also known as a ‘TA6’) regarding if the property is affected by Japanese knotweed.

The knotweed was located at the bottom of the garden and has not been reported to be causing any damage to the house or another structure. Despite Mr Henderson arguing that he genuinely had not known about the plant and even relying on a surveyor’s report when he purchased previously which did not identify it, Judge Jan Luba KC ruled the seller had made a misrepresentation. A misrepresentation made by a seller to a buyer can be sued upon by the buyer. Mr Downing was awarded £32,000 plus his legal fees paid up to the sum of £95,000.

Moore Barlow’s advice

Therefore, we always advise our seller clients to tick ‘not known’ on the TA6 form when asked about the presence of Japanese knotweed on the property. Whether they own a country house and garden, a farm or a landed estate.

In the words of Donald Rumsfeld “there are known knowns…and known unknowns”. Let your answer regarding the presence of Japanese knotweed be a known unknown.