Japanese Knotweed was introduced to the UK in the 19th century. It was considered to be an ornamental plant and was also used to stabilise the gravel under railway tracks. Today it is the most invasive plant in the country and is very difficult to remove from land it infects. The roots can grow up to 3 metres underground and, even if it is removed, a small piece of root can re-establish the plant.
The plant can grow extremely quickly during its growth season between April to September. It has been known to damage concrete foundations and affect the structural integrity of buildings. This, of course, affects the ability to insure, mortgage and sell any land or property where the plant’s presence is known.
The general principle of ‘caveat emptor’ (let the buyer beware) means the seller is not obliged to disclose information to a buyer unless the buyer raises pre-contractual enquiries. The standard residential and agricultural land pre-contract enquiries contain questions relating to Japanese Knotweed. However, the standard enquiries for commercial properties ask for any details of rising damp, rot, any fungal or other infection or any infestation. This would arguably cover Japanese Knotweed, but it is perhaps prudent to add a supplementary enquiry if you think the plant could be an issue.
Basic environmental searches typically report on information which is publicly available. They also do not include a site visit. If you find out that Japanese Knotweed is a risk on a property that you wish to purchase or lease, you can order specialist knotweed surveys which should give you a better understanding of the risk.
Enquiries relating to Japanese Knotweed apply to leases as much as purchases. If it is present on the landlord’s property, prospective tenants must consider their own liability in respect of:
- repairing any damage caused by the plant to the property
- any third parties whose land is affected by the presence of the plant
- any management or eradication costs
- any statutory or local authority requirements that arise from the plant’s presence
This list is not exhaustive and there may be more issues to consider depending on the circumstances. Tenants who, after taking possession, learn of the presence of Japanese Knotweed should examine the terms of their lease carefully; they may be required to pay substantial sums that they had not anticipated.
What if I already have it on my land?
Having Japanese Knotweed on your land is not a criminal offence in itself and it may never cause you or your neighbours any issues; however, if it does spread onto your neighbour’s land, a dispute can arise.
The recent case of Williams v Network Rail Ltd  UK CC has been considered by some as a landmark case after the Claimants were successful at trial. The Claimants made an application for an injunction from Network Rail to treat the Japanese Knotweed that had spread onto their land and applied for damages for interference with the quiet enjoyment of their home.
The basis of their claim was that Japanese Knotweed from Network Rail’s land had encroached onto their property causing a nuisance and interference with their quiet enjoyment of the property. As a result, the value of the Claimant’s property had been affected, as it can be difficult to secure a mortgage where Japanese Knotweed is within a properties boundary.
The Judge held that the Japanese Knotweed had caused loss of enjoyment of the property and awarded £10,500 in damages towards the diminution of the property value and £5,000 towards the cost of its removal.
This means that if the plant invades your neighbours’ land, you could potentially be creating an actionable nuisance and you could be taken to court. This is yet another reason why the plant should be eradicated before you purchase or lease a property.
Due to the invasive nature of the plant and damage that it can cause, legislation bans the planting or spread of Japanese knotweed in the wild. Additionally, it is classed as a controlled waste under the Environmental Protection Act 1990 and failure to dispose of it correctly may lead to a criminal prosecution.
Proactive rather than reactive
The damage to the property and its value caused by Japanese Knotweed can be substantial, but there are effective methods from specialists to remove the plant from a property. If, prior to purchase or lease, suitable pre-contract enquiries are made, which reveal the existence of Japanese Knotweed, the plant can be effectively dealt with. There is no harm in asking the question and you may be very glad that you did.
In the event that a dispute arises in relation to Japanese Knotweed with your neighbour, try and negotiate with them in the first instance as the Court may look for evidence that the offending party took reasonable steps. Nonetheless, it is important to remember that claims need to be made within six years of the dispute arising and, given the alarming rate at which Japanese Knotweed can grow, it is better to seek advice early to protect your interests and your property.
If you have been affected in any way by Japanese Knotweed, please feel free to contact our Litigation Department, Commercial Property Department or Regulatory Department who will be ready and able to assist you.