Invasive plants like Japanese Knotweed could be easy to conceal during the Winter as it dies back, and more widely spread because of extreme weather events like flooding say two specialists.
Conveyancers and homebuyers are being warned to be vigilant as up to 1 in 20 properties could be affected by Japanese Knotweed say Environet, a specialist in the removal of invasive plants. A 2024 YouGov survey revealed 15% of sellers would choose not to disclose knotweed to buyers or take any action to remedy it before a sale, despite the inclusion it specifically in the TA6 property protocol form, resulting in ‘hundreds’ of misrepresentation cases brought by ‘disgruntled buyers’ every year in a bid to recover treatment costs.
Emily Grant, director of Environet, said:
“Every spring we are contacted by people who have bought properties over the winter and then received a nasty shock in spring when knotweed shoots have begun to emerge. As well as removing the dead canes and covering the crowns, we’ve seen cases where knotweed has been covered with decking, had a pathway or patio laid over it, or even a shed. One client only understood why the back garden of the home he had recently bought had been concreted over when knotweed shoots began to spring up around the edges.
“Knotweed cannot be killed by concreting over it, burning it or applying over the counter weedkiller. Unless it’s professionally excavated or herbicide-treated over several growing seasons, it will grow back each year. Buyers viewing properties at this time of year should check carefully for evidence of knotweed and ask their RICS surveyor to be extra vigilant for signs of concealment. If in doubt, commission a specialist to carry out a Japanese knotweed survey, backed by a warranty.”
Where Japanese Knotweed is found, as long as a professional treatment plan is in place with an insurance-backed guarantee, most mortgage lenders will offer a loan and the transaction can go ahead say Environet.
Meanwhile extreme weather events like the flooding recently experienced by many has had a ‘significant and detrimental impact’ on the spread of invasive plant species says Richard Podmore of Japanese Knotweed Control.
“The spread of invasive plants has a significant impact on the UK’s environment and economy. Invasive plants outcompete native species for resources, leading to a decline in biodiversity. They can alter the structure and function of ecosystems, impacting wildlife and their habitats. Invasive plants can cause significant economic damage to infrastructure, agriculture, and property values. Floodwaters act as powerful carriers, transporting seeds of invasive plants like Japanese Knotweed and Himalayan Balsam over vast distances.”
says Podmore, adding
“Seeds and plant fragments can become lodged in new locations, germinating and establishing new colonies. Flooding erodes riverbanks and disrupts soil, creating ideal conditions for invasive plants to take root. Plants often thrive in disturbed areas, outcompeting native species and floodwaters can damage or destroy control measures put in place to manage invasive plant populations, such as physical barriers or herbicide treatments. The increasing frequency and severity of flooding events in the UK pose a significant challenge to the management of invasive plants.”
Although the fifth edition of the TA6 property information is currently going through a consultation after uproar over the length of the new form, and the nature and liability of the additional inclusions, Japanese Knotweed has been part of the TA6 since the third edition. In the fourth edition the wording was updated to extend the obligation on sellers to identify whether there is Japanese Knotweed present not only inside the boundary of the property, but ‘an area adjacent to or abutting the boundary.’ The Law Society explanatory notes for sellers and buyers go on to state that, ‘if you choose ‘No’ as an answer, you must be certain that, even if you cannot see any growth above ground, no rhizome (root) is present in the ground of the property or within three metres of the property boundary.’
