Overview

• Propertymark highlights Wiltshire as a potential knotweed ‘time bomb’ zone and cautions that unchecked seasonal growth can breach foundations and masonry.
• Environet’s interactive map records over 100,000 UK infestations and flags Bristol, Merseyside and newly afflicted Wiltshire among the worst-hit areas.
• Japanese Knotweed can grow up to 10cm per day, forcing through concrete, cavity walls and damaged mortar and shaving as much as 15% off property values.
• Effective control demands either targeted herbicide programmes or complete excavation with a detailed post-treatment management plan to curb regrowth.
• UK law requires sellers to disclose any knotweed presence or face prosecution, and most lenders will back mortgages if buyers present certified treatment regimes.