It is a fast-growing invasive perennial weed that grows underground and can cause damage to structures and property.
The Environment Agency considers Japanese knotweed as the “most common” of four invasive knotweed plant species in the UK, as well as dwarf knotweed, giant knotweed and bohemian (hybrid) knotweed.
Commenting on how to spot Japanese knotweed in your garden, Japanese Knotweed Ltd noted: “Key features are the zig-zag stem structure, ‘shovel’ shaped leaves and white flowers that emerge in summer. The stems can grow up to 7ft high.
@davetheplantman Japanese knotweed #gardening #plants #gardeningforbeginners ♬ original sound – Dave The Plantman
“In winter it looks completely different with only dark brownish red stems being visible above ground.”
York Japanese knotweed hotspots revealed in heatmap
Currently, York has 44 infestations of Japanese knotweed, according to Environet.
You can search the heatmap by postcode here to see if your property in North Yorkshire is in a high-risk area.
Environet estimates that “approximately 5% of homes across the UK are currently affected by Japanese knotweed either directly or neighbouring an affected property, typically impacting property prices by around 5% -or up to 10% in severe cases”.
Elsewhere in Yorkshire, there are other Japanese knotweed hotspots to be aware of in case you are thinking about moving house anytime soon.
The highest is Rotherham with 543 infestations and Sheffield follows closely with 517.
Huddersfield has a reported 168 infestations and Doncaster has a slightly lower amount of 134.
Barnsley is the least infested area with 118 reports.
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In total, there are 2,333 known Japanese knotweed occurrences across Yorkshire, with one in every 5km2.
Nic Seal, founder of Environet, explained: “At this time of year knotweed has emerged from the ground and by the end of April or early May it will be growing as much as 10cm per day and covered in bright green heart-shaped leaves. The best way to protect your property is to make sure you know what knotweed looks like, so you can act early if it appears in your garden or is threatening to encroach onto your property.
“Yorkshire is home to some significant knotweed hotspots such as Rotherham and Sheffield. Anyone living near or moving to one of these areas should check their garden carefully and enter their postcode into Exposed to find out how many occurrences are nearby and if in doubt, seek expert help.”
