IT’S A menace and Reading is a hotspot for it – but thankfully people are growing more aware of its problems.
Japanese knotweed is a plant that spreads via powerful root system and can cause damage to driveways, patios, drains and walls and cause legal disputes between neighbours when it encroaches across boundaries.
New research shows that awareness in the south east is now at 83% – 5% higher than five years ago – as homeowners come up against the problem when buying and selling property.
YouGov for Environet UK found that approximately 7% of homes in the region are now affected by knotweed, with Environet’s Japanese knotweed heatmap, Exposed, showing the Ding as one of the towns where it is the biggest problem.
Earlier this year The Royal Institute of Chartered Surveyors (RICS) relaxed its guidance to encourage herbicide-based methods of dealing with Japanese knotweed, which aim to control the plant rather than eradicate it, but the research shows that buyers would be considerably less comfortable purchasing a property where there’s a high chance the plant is still present and induced into dormancy.
This is likely to affect their willingness to buy the property and the price they’re prepared to pay.
According to the survey of more than 2,000 people, 63% of respondents in the South East would be uncomfortable buying a property that had been herbicide treated for a knotweed infestation, compared to 29% of people who would be uncomfortable buying a property with knotweed where the plant had been excavated from the ground.
Herbicide treatments can only be carried out during the growing season, from May to September, and can take two to three years to complete. The root system remains in the ground and can be prompted to regrow if disturbed, such as through landscaping or building work.
Excavation of knotweed can be carried out at any time of year and is the most effective way of dealing with the problem, removing the rhizome from the ground with immediate results.
While there is often a ‘knotweed stigma’ impacting the appeal of properties affected by the invasive plant, as long as an infestation is professionally treated with an insurance-backed guarantee, mortgages can be secured and sales can proceed.
If knotweed was discovered after moving into a property, more than three quarters (78%) of people in the South East would be concerned, the main reasons being damage to property and gardens (selected by 81% of respondents), the cost of treatment/removal (80%), problems selling in the future (68%) and the potential impact on the property’s value (67%). Fewer than half (47%) selected the risk of the plant spreading into adjoining property as a concern, despite the fact that expenses arising from legal claims for encroachment can dwarf all other costs.
Worryingly, 22% of people stated they wouldn’t be concerned to discover knotweed on a property after they had bought it because they believe they can treat the problem themselves. Knotweed’s extensive underground root system makes it notoriously difficult to remove and it can regrow from a tiny fragment left in the soil, which is why mortgage lenders insist on evidence of professional removal and guarantees for the work before they will offer a loan on an affected property.
Nic Seal, Founder and MD of Environet, said, “Awareness of Japanese knotweed and the problems it can cause is growing in the South East, making it easier for people to identify the problem, deal with it effectively and protect themselves from legal claims arising when the plant spreads.
“If you do discover knotweed, the best way to preserve your property’s value is to professionally excavate the infestation, secure a 10-year insurance-backed guarantee and be honest and up front with potential buyers when you come to sell.”
