Bucks’ ‘million-pound town’ has been revealed to have the highest number of Japanese knotweed cases in the county as the UK’s most invasive plant enters its spring growth phase.

Japanese knotweed expert Environet has revealed the latest hotspots using data from its interactive online tracker, Exposed: the Japanese Knotweed Heatmap – and Beaconsfield is high on the list for Bucks.

Populated with over 54,000 known infestations of Japanese knotweed, charting the spread of the plant across the UK, Exposed informs homeowners and potential homebuyers of the local presence of knotweed and the potential risk to their property.

Users can enter a postcode to discover the number of reported knotweed sightings nearby, with hotspots highlighted in yellow or red.

The Buckinghamshire Japanese knotweed hotspots for 2021, according to  Environet, are:

  • Beaconsfield – 21
  • High Wycombe – 20
  • Amersham – 18
  • Chesham – 18
  • Marlow – 13

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After its winter hibernation, knotweed begins to grow in March or April, depending on the local ground temperature, reaching up to three metres in height by mid-summer.

Bucks Free Press: Japanese knotweed hotspots around Buckinghamshire. Credit: Environet UKJapanese knotweed hotspots around Buckinghamshire. Credit: Environet UK

Homeowners spending more time in their gardens this spring may notice purple or red asparagus-like shoots now emerging from the ground and quickly growing into lush green shrubs with heart or shovel-shaped leaves and pink-flecked stems.

Pushing up through cracks in concrete, driveways, patios, paths, drains and even the cavity walls of our homes, Japanese knotweed can reduce a property’s value by 10 per cent according to Environet, and make it difficult to sell, unless a professional treatment plan is in place with an insurance-backed guarantee to satisfy mortgage lenders.

According to Environet’s research, around five per cent of homes are currently affected, either directly or indirectly (neighbouring an affected property), knocking around £20 billion off UK house prices.

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Luke Walton, Environet’s Regional Director for Berkshire, said: “Knowledge is power when it comes to Japanese knotweed and this heatmap is invaluable to homeowners and buyers who want to assess the risk in their local area.

“With the stamp duty holiday extended and lockdown restrictions beginning to ease, the property market is busier than ever – but failing to carry out the appropriate checks for knotweed can turn out to be an expensive mistake.

“Despite its fearsome reputation, with professional help, the plant can be dealt with and the value of a property largely restored.

“I’d urge anyone buying or selling a property, or homeowners wishing to preserve the value of their home, to be vigilant for signs of spring growth and check Exposed to see whether they live in a high-risk area.”

You can find the tracker at environetuk.com/exposed-japanese-knotweed-heat-map.