Japanese Knotweed in Leeds: Map reveals invasive plant hotspots in Yorkshire as experts call for 'vigilance'
Experts have issued warnings over the spread of Japanese knotweed, with new data revealing the areas in Yorkshire where the invasive plant is most prevalent.
Japanese knotweed is a highly invasive plant that, if left unchecked, can seriously damage, and in some cases even destroy, your home.
Invasive plant experts Environet estimates that around 5 per cent of homes across the UK are currently affected by the weed, either directly or neighbouring a property which has been affected.
Since its introduction to our shores in Victorian times, the plant has spread widely, with an average of 1.1 occurrences in every square mile in England, Environet claimed.
To raise awareness and to help prevent damage, the interactive Exposed: The Japanese Knotweed heatmap tracks and maps reported cases and hotspots around the UK. Users can enter their postcode to discover the number of verified knotweed reports within a 4-kilometre radius, with hotspots highlighted in yellow, orange, or red.
According to the map, there have been 179 reported incidents in Leeds, with Wakefield logging 61 incidents.
Japanese Knotweed begins to emerge in early spring, quickly growing into lush, green shrubs. It can be identified by its pick-flecked stems, heart-shaped leaves, and bamboo-like canes.
With underground rhizomes that can grow up to three metres deep and up to seven metres horizontally, it can emerge through concrete cracks, tarmac driveways, prains, cavity walls, and pathways, causing serious problems for homeowners.
While serious structural damage is uncommon, the presence of Japanese knotweed often sparks neighbourly disputes and can knock around 5 per cent off a property’s value, as mortgage lenders typically insist it’s dealt with before a sale, according to Environet. A 2023 DEFRA report estimated the weed costs the UK economy close to £250 million each year.
Environet Director Emily Grant said public engagement is crucial to tackling and preventing the spread of knotweed, and by reporting new sightings, homeowners can help control the plant and protect property values.
She 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. 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 [email protected] 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.”