Japanese knotweed hotspots in Barking and Dagenham revealed

Japanese knotweed is a plant species native to east Asia and was introduced to the UK in the 1800s.

It can grow up to four inches a day and forms dense thickets which can kill native plant species and damage buildings.

According to invasive planet experts Environet, it is now widely recognised as a “pest species that outcompetes native plants and causes damage in the built environment”.

How Japanese knotweed can look in the summer months (Image: Environet) Using Environet’s data map, we have taken the average number of Japanese knotweed sightings from five postcodes in each area around Barking and Dagenham to provide an average number of sightings for that area in the past 10 years.

Central Barking (IG11) had the highest number of sightings by a large margin with an average of 509 in each neighbourhood.

Barking Riverside (IG11) had the next highest number of sightings with 393 spotted on average in these neighbourhoods.

Chadwell Heath registered the next most knotweed sightings with an average of 343 in each RM8 postcode.

Becontree neighbourhoods (RM9) averaged 315 sightings whilst central and east Dagenham neighbourhoods (RM10) averaged 279 and 250 sightings respectively.

The heatmap shows which areas have had the most sightings in the last 10 years (Image: Environet) New sightings are added daily by Environet.

Environet director Emily Grant 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.”

Japanese knotweed can grow in cracks in rocks (Image: Environet) A 2023 Department for Environment, Food and Rural Affairs report put the cost of tackling knotweed to the UK economy at almost £250 million a year.

Emily added: “Mature plants flower around August, when they produce clusters of tiny white blooms.

“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.”