NEW DATA has revealed the Dorset hotspots with the ‘UK’s most invasive plant’, Japanese Knotweed.

The invasive plant species is responsible for damaging homes, pavements and drains and can spread up to seven metres horizontally.

As the Japanese knotweed growing season gets underway, invasive plant specialist Environet UK has revealed the knotweed hotspots for spring using data from its online map.

There are currently almost 55,500 known occurrences of the UK’s most invasive plant. 

The Dorset Japanese knotweed hotspots for 2022 are: Dorchester with 24 infestations in a 4km radius, Poole (23), Weymouth (22), Bournemouth (21) and Swanage (18).

Knotweed hibernates over winter but in March or April it begins to grow, with red or purple spear-like shoots emerging from the ground which quickly grow into lush green shrubs with pink-flecked stems and bamboo-like canes.

For homeowners, the plant can pose serious problems if left unchecked, with the potential to grow up through cracks in concrete, tarmac driveways, pathways, drains and cavity walls.

The roots can grow as deep as three metres and spread up to seven metres horizontally. While serious damage to property is rare thanks to regulation which requires knotweed to be dealt with, it commonly impacts use of the garden, causes legal disputes between neighbours and can impact a property’s value by around five per cent.

According to Environet’s research, approximately five per cent of homes are currently affected by knotweed, either directly or indirectly.

What to do if you think you have Japanese knotweed:

  • Commission a professional Japanese knotweed survey to find out the extent of the infestation, where it originated and the best way to tackle it.
  • Arrange professional treatment, usually herbicide or excavation, and always be sure to secure an insurance-backed guarantee for the work.
  • If you’re buying a property and you want to be sure it’s clear of knotweed, particularly if it’s located in or near a hotspot, arrange a detection dog survey.

To view Japanese knotweed infestations in your area, visit: https://environetuk.com/exposed-japanese-knotweed-heat-map