There is a general lack of awareness of the legal responsibility of owners to prevent Japanese knotweed from spreading with reportedly only 36% of property owners knowing they could be sued and just 18% of owners aware that they could face prosecution. This blog is intended to give you some guidance on the laws relating to Japanese knotweed and what can be done if you are buying or selling a property with Japanese knotweed present.

What is Japanese Knotweed?

Japanese knotweed originally came to the UK as a garden plant after being used in Japan to stabilise sand banks. Plant hunters in the Victorian era were drawn to the plant because it looked like bamboo and grew very well and rapidly. However, Japan has diseases and animals that are effectively able to maintain the knotweed planted, unlike the UK, which lacks the diseases and animals and therefore the plant grows unmaintained causing mayhem and destruction in its path.

During the winter months, the plant dies to ground level however stem growth reoccurs each year. It can therefore be difficult to detect in properties or land during the winter months. In spring, the plant starts to regrow initially from pink buds at ground level, there will then be reddish-purple colour shoots which emerge that resemble asparagus tips. The detection of the knotweed can still be difficult, however, if there are reddish-purple shoots or pink buds around brown bamboo-like canes then this is usually a good indication that there is knotweed present.

By the summer there will be thick canes which resemble bamboo and that can grow up to 7ft tall. During the summer months a mature knotweed plant can grow at a rate of 10cm a day and will often outgrow surrounding plants. The colour of the bamboo-like canes are green but they have purple fleck characteristics. The canes grow leaves which are heart shaped and up to 14cm in length. The leaves are quite distinctive and have purplish or pink veins. The plant also produces white flowers in the late summer and early autumn. The flowers form in clusters and are small.

Japanese knotweed can be mistaken for other similar looking plants and often Bindweed gets mistaken for Japanese knotweed. The reason for this is that both plants have very similar characteristics, particularly in Spring when both plants start to regrow and eventually have similar large, heart shaped leaves, both plants also grow very quickly.

The main characteristic difference between these two plants, however, is that Bindweed is a climbing plant and wraps itself around things whereas, Japanese knotweed is a freestanding plant which does not need any support. The other difference between the two plants is that Bindweed has large white or pink trumpet shaped flowers whereas Japanese knotweed has clusters of small white flowers. The flowering stage also differs between the two plants, Bindweed flowers appear in late spring, early summer whereas, knotweed flowers appear towards the end of summer, early autumn.

Why is it a problem?

Japanese knotweed is an invasive and destructive plant which can be found all over the UK. It is usually found in nutrient-poor or contaminated soils and therefore most commonly grows in derelict land in urban areas and along railway lines.

The Wildlife and Countryside Act 1981 makes it an offence to plant or cause Japanese knotweed to grow due to its destructive nature. The knotweed grows very quickly and grows usually very deep underground, spread over a large area. In the spring when the shoots begin to grow, they are capable of imbedding into cracks and gaps in buildings as well as hard surfaces such as concrete and tarmac, which can cause significant damage over time.

The cost for eradicating the knotweed is one of the main issues associated with this plant as the costs can run into hundreds of thousands of pounds for large infestations. There is also the cost of repairing damage caused by the plant to any buildings or surfaces in the property.

Due to the laws and regulations that concern the knotweed, the removal of the plant needs to be done by a specialist Japanese knotweed contractor who must also be a registered waste carrier to safely remove the knotweed.

Attempting to dig out the plant without professional help may be possible however, this leads to the issue of disposal, Japanese knotweed is classed as controlled waste under the Environmental Protection Act 1990. To dispose of controlled waste, a license is needed to dispose of the material at a specific landfill site. It is an offence to dispose of the knotweed in any other way. If disposed of in another way, individuals or companies could be fined up to £5,000 or be sent to prison for up to 2 years for allowing contaminated soil or plant material from controlled waste to spread into the wild.

The Anti-Social Behaviour, Crime and Policing Act 2014 has been reformed to enable notices to be served on individuals or companies which enforces them to take action to control Japanese knotweed. This means that ASBO’s could be served for failing to control the spread of the knotweed.

An example of the Anti-Social Behaviour, Crime and Policing Act 2014 being used in practice can be shown by a case in December 2018, held in the Bristol Magistrates Court where the Defendant (MB Estate Ltd) was ordered to pay £18,000 for failing to prevent the spread of Japanese knotweed after they failed to respond to a Community Protection Notice served on them in 2017 by the Bristol City Council in relation to the knotweed.

Finally, the spread of knotweed onto a neighbour’s property may also give rise to liability under a private nuisance claim. In Network Rail Infrastructure Ltd v Williams the Court of Appeal Judge Terence Etherton stated in his judgment that:

‘The mere presence of Japanese knotweed’s rhizomes imposes an immediate burden on the owner of the land in terms of an increased difficulty in the ability to develop, and in the cost of developing the land, should the owner wish to do so.

Selling property affected by Japanese Knotweed

There is an onus of responsibility on property owners who have Japanese knotweed present on their property or land. The Property Information Form (TA6) asks the Seller to confirm whether the property which they are selling is affected by Japanese knotweed.

The presence of the knotweed usually negatively impacts the marketability and value of the property due to the damage caused by the knotweed and the costs involved in removing it.

When completing the TA6, the Seller must highlight information that should be provided to the Buyer and details of any treatment plans or maintenance plans should be supplied. It is important to note that if the Seller states that they are not aware of any knotweed present on the property or land, and it later transpires that they were aware or ought to have been aware, then the Buyer may pursue the Seller for compensation.

If Sellers are aware that knotweed is present on the property or land being sold, it is imperative that action is taken to try to remove the knotweed prior to completion or to employ the services of a specialist to put in place a Japanese knotweed management plan.

Buying a property affected by Japanese Knotweed

The presence of Japanese knotweed on the property will usually be stated in the Property Information Form (TA6) however, the Buyer should also consider checking the property themselves for any indication that the knotweed is present and obtaining an independent survey of the property. The cost of carrying out an initial survey is significantly less than the expense of having to extinguish the plant from the property.

It is not uncommon for Lenders to refuse to lend on properties which are affected by knotweed and Lenders often require assurances that the knotweed will be eradicated before agreeing the funds.

Due to the costs involved and damage that can be caused by the knotweed, the property is usually less valuable.  Some Lenders will also refuse to lend on properties where knotweed is within 7 meters of the boundaries of the property or land due to its invasive nature.

The presence of knotweed can also in some cases delay development or the land transaction due to the requirement for removal. It is therefore preferential that the Seller remove the plant prior to completion of the sale.

If a Buyer is purchasing property or land which is known to have Japanese knotweed it is recommended that they:

  1. Obtain a Japanese knotweed search report
  2. Employ the services of an invasive weeds’ professional
  3. Obtain images of the plant and where it is located
  4. Request details of any previous works carried out as well as a copy of a Japanese knotweed management plan if there is one and ensure that the plan is fit for purpose, provides a long-term guarantee and can be transferred to the Buyer
  5. Consider negotiating a reduced purchase price
  6. Obtain an insurance policy to cover any damage caused by the knotweed for both the property being purchased as well as any nuisance or damage caused to neighbouring properties.
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