Japanese horticulture ties legislation up in knots

Originally introduced to the UK in the 1850s as an ornamental plant and animal feed, Japanese knotweed (Fallopia japonica) is described by the Environment Agency as ‘indisputably the UK’s most aggressive, destructive and invasive plant’. Estimates now suggest at least one infestation in every 10km² in the UK.

Knotweed can grow three
to four metres in a ten week growing season, and as little
as 0.7 grams of rhizome can produce a new plant within
only ten days. The rhizomes
can spread to a depth of
three metres, and seven metres horizontally. This strong growth and invasive root system can damage concrete foundations, buildings, roads, paving and retaining walls.

Unmortgageable property

As a result of the destructive nature of knotweed, and the potentially huge cost – in time and money – of dealing with
it, its presence can damage a property owner’s interest, reducing a property’s value or preventing a sale, and making
it unmortgageable (if there is evidence of knotweed or there
is a history of it in the area,
a specialist survey may be required before a lender will consider making any loan).

It is not surprising then that the presence of knotweed can lead to litigation. What is surprising is the relative dearth of case law relating specifically
to knotweed. As well as claims against a neighbour (in nuisance) and against a surveyor/valuer (in professional negligence/breach of contract), claims may be brought against a seller in misrepresentation.

The Law Society property information form contains the following ‘instructions to the seller’: ‘If you do not know the answer to any question, you must say so. If you are unsure of the meaning of any questions or answers, you should ask your solicitor’. The form is important for both buyer and seller because the seller’s replies are representations and buyers are informed that they ‘are entitled to rely on the replies given to enquiries by the seller’. When the seller replies to questions on the form, therefore, he should give careful consideration to the content of the answers.

Since March 2013 there has been a specific section dealing with knotweed; the form asks sellers: ‘Is the property affected by Japanese knotweed? – Yes/No/Not known.’ Plainly, if a seller is aware that the property is affected, he must answer ‘yes’. What if a seller is unsure though? If he answers ‘no’, it is likely this would be considered
a positive assertion that he had checked, and that the property
is clear. Thus if the seller answers ‘no’, based on the best of his knowledge, but it later transpires that knotweed is present, the seller may be liable to the buyer for misrepresentation.

Suspicious buyers

The position would likely be similar even if the seller qualified his answer with a phrase such as ‘not so far as the seller is aware’, as this may still be seen as a representation that the seller
has taken reasonable steps to ascertain the correct reply. Thus it would seem that if the seller does not know whether or not the property is affected by knotweed, he should answer ‘not known’ rather than ‘no’, but this non-committal response could well cause the buyer to become suspicious – has the seller checked? Is he hiding something?

An alternative approach, when the seller does not know for sure but has no reason to believe that the property is affected by knotweed, would be to answer ‘no’ but add the caveat that ‘no warranty is given, and the buyer is recommended to obtain a suitable survey to answer this question’. In any event, a buyer would always be best advised to commission a survey, and the form makes clear that (at least in relation to the physical condition of the property) ‘the replies should not be treated as a substitute for undertaking a survey or making independent enquiries, which you are recommended to do’.

Finally, if the seller subsequently becomes aware, before exchange of contracts, that his original reply was inaccurate, or the circumstances have changed so that the original reply is no longer accurate, he should inform the buyer. The form clearly states that if the seller later becomes ‘aware of any information which would alter any replies you have given, you must inform your solicitor immediately. This is as important as giving the right answers in the first place’. If the seller does not do so, he could be liable for misrepresentation. SJ

Andrew Skelly is a barrister practising from Hardwicke