Japanese Knotweed, Fallopia Japonica (JKW) is native to Asia and was brought into Britain by the Victorians. It was widely used to stabilise railway banking’s due to its rapid growth of up to 10cm a day in summer and is root structure which stabilised the soil.
The plant itself has no natural enemies in the UK which can prevent its growth however trials are ongoing to control its growth with Fungus and Insects. It is now listed as one of the world’s 100 worst invasive species
It is not illegalto have Japanese knotweed in your garden, but if JKW is growing on your property you should aim to controlthis invasive non-native plant to prevent it becoming a problem in your area. However it is against the law to allow the spread JKW and you can be prosecuted if it spreads on your neighbours land. Under the provisions made within Schedule 9 of the wildlife and countryside act 1981 it is an offence to cause JKW to grow in the wild.
It can often take several years to eradicate a JKW infestation due to its rapid growth, as it can grow through walls, tarmac and concrete. The main treatment methods involve spraying, stem injection or mechanical excavation and removal, all of which are costly.
According to the UK government the cost of controlling JKW had hit 1.25 billion in 2014, furthermore, it cost 70 million to eradicate the JKW from 10 acres of land at the London Velodrome and aquatic centre prior to the 2012 London games.
Mortgages lenders are now becoming sceptical about lending on properties affected by JKW following a recent court of appeal case earlier this year. This landmark case Waistell & Williams vs Network Rail Infrastructure Ltd has now set a precedent on the presence of JKW.
The Court of Appeal judgement found that although the mere presence of knotweed on an adjoining property may not be capable of presenting a nuisance, once JKW had encroached onto another property, that does amount to physical damage and an actionable nuisance.
The Court of Appeal dismissed Network Rail’s appeal and upheld in most part the ruling made in February 2017 at Cardiff County Court, that Network Rail had caused an actionable nuisance by failing to control JKW. As a result, Mr Waistell was awarded damages for the cost of treatment and the residual diminution in value of his property after the treatment had been carried out.
Whilst it is possible to eradicate JKW, the cost implications of doing so are high, early identification is essential to prevent the spread. If you suspect you may have JKW on your property it is essential you seek advice from a specialist.