Gardner Leader

A 'knotty' problem

September 2007

Developers face a ‘knotty’ problem

Robert Green, Commercial Associate at Gardner Leader solicitors in Newbury, takes a look at the background to the introduction of the Code of Practice for dealing with Japanese Knotweed on development sites and suggests how developers might overcome this problem.

We tend to overlook the power of nature until it is dramatically brought to our attention; the recent flash floods that brought havoc to many parts of the country are just one example. Well intentioned but misguided human activities can also cause damage; the introduction to this country of Dutch Elm Disease by the importation of untreated logs is such an example.

In the 19th Century plantsmen scoured the world looking for exotic species of plants which would enhance the ornamental gardens of the period. One such plant, Fallopia Japonica Var Japonica or Japanese Knotweed, was introduced into this country as such an ornamental plant. It has no natural pests or diseases in this country and consequently has been growing vigorously and unchecked. In addition to the damage that an infestation of this plant can do to the environment, it is also capable of causing considerable damage to buildings and hard surfaces when it is allowed to flourish beneath them.

Such is the concern with which Japanese Knotweed is viewed, that the Environment Agency has now published a Code of Practice for dealing with Japanese Knotweed in connection with development sites. The Code of Practice, which can be downloaded from the Environment Agency Website, sets out ecological information regarding the plant, together with advice on how to prevent the plant from spreading and how best to manage an infestation problem.

Faced with an infestation on a potential development site, a developer must consider how best to remove this pest. Treating the area with herbicide is one possibility, but the recommended period for such treatment is three years; an unacceptable delay to most developers who will want to start work on site as soon as Building Regulation approval has been obtained. Moreover, if Japanese Knotweed is treated with herbicides and then cut down, the resulting waste may be classified as hazardous waste within the meaning of the Hazardous Waste Regulations 2005, which will greatly complicate the eradication of the weed as well as increase costs.

Treatment on site by the physical removal of the weed and soil contaminated with it is likely to be the quickest remedy available. However, in the opinion of the Environment Agency, the disposal of any soil or plant waste which is contaminated with Japanese Knotweed, may be viewed as “controlled waste” within the meaning of the Environmental Protection Act 1990, so that disposal of such waste without a licence will constitute an offence within the meaning of Section 33(1) (a) and (b) of that Act. Thus any such waste will have to be transferred to an authorised person, being a registered carrier or exempted from registration by the Control Waste (Registration of Carriers and Seizure of Vehicles) Regulations 1991. The provisions of the Environmental Protection (Duty of Care) Regulations 1991 must also be complied with in relation to the transfer of such waste.

Faced with these difficulties, clearly the simplest solution from the developer’s point of view is to ensure that any potential development site is clear of the weed - difficult to assess if viewing the site in winter. Alternatively to seek warranties from the seller of the site that it is clear of weed and to enforce those warranties if Japanese Knotweed rears its not unpleasant but distinctly unwelcome head, after completion of the sale and purchase has taken place.

Details: Robert Green Tel. 01625 508080

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