Bristol has been named the top hotspot for Japanese knotweed in England, with 33.91 cases per square mile, according to data from Environet’s Exposed: The Japanese Knotweed Heatmap.
Merseyside followed with 11.87 cases per square mile, then Greater London at 7.74, and Lancashire at 7.25.
Greater Manchester, the Isle of Man, Channel Islands, Isle of Wight, Derbyshire and Nottinghamshire also ranked high for knotweed sightings.
On average, England has 1.1 cases per square mile and Wales has 3.9.
Emily Grant, director at Environet, said, “By mapping verified sightings, we’re helping people understand the level of risk in their local area and encouraging early identification and treatment.
“Vigilance is the best way to protect your property from Japanese knotweed, making sure you tackle it as early as possible before it becomes well established.
“At this time of year, knotweed is in full growth mode and easy to spot with its bright green heart-shaped leaves which grow in a zigzag pattern up the stems.”
Grant added: “Mature plants flower around August, when they produce clusters of tiny white blooms. If you do suspect you have knotweed on or near your property, you can email a photo to us at expert@environetuk.com and we’ll identify it for free.
“If it is knotweed, a survey will determine the extent of the infestation and the best way to treat it, whether that’s digging it out of the ground, herbicide treating it or a combination of both.
“Public engagement is key in the fight against knotweed, and by reporting new sightings homeowners can play an important role in controlling this invasive plant and protecting property values.”
