Dorset residents are warned to be vigilant, as the invasive Japanese knotweed begins to enter its spring growth phase.

A recent study by Environet UK has detected that Weymouth and Dorchester, as well as parts of west Dorset are hotspots for the rapidly growing weed.

The firm's 'heatmap', an interactive online map of sightings in the UK to inform residents, has already been populated with thousands of infestations.

Japanese knotweed is described by the Environment Agency as “indisputably the UK’s most aggressive, destructive and invasive plant”. It grows at a very fast rate, in parks and gardens as well as along railways and waterways and by summer can reach up to 3m in height. It is known to be very difficult to treat without the use of a professional.

Homeowners should be on the look out for reddish/purple shoots appearing from the ground, these can grow up to 2cm per day and rapidly form dense stands of bamboo-like stems. By late spring the plant will be covered in heart-shaped green leaves.

According to Environet UK, around 4 to 5% of the UK’s houses are currently affected, whether directly or indirectly. They urge however, not to panic despite the plant’s fearsome reputation.

Environet has advised homeowners first to identify any suspicious plants by emailing a photo to expert@environetuk.com.

If it is confirmed as Japanese knotweed, it most cases it can be dug up by a professional during the lockdown period. As the work is undertaken outside, it can still be done whilst observing social distancing measures. In cases when this is not possible, Environet has urged not to panic, as while knotweed should be treated as soon as possible, it usually won’t cause much harm if left growing for a short while.

They have also warned against attempting to remove the plant yourself, as many standard measures are not effective at killing the plant’s root system and could even contribute to the spread.

Nic Seal, Founder and MD of Environet, said, “Our message to homeowners who discover Japanese knotweed growing in their garden over the next few weeks is not to panic and resist the temptation to deal with it themselves.

A failed attempt to dig it up could help it spread and spraying the plant with herbicide makes professional treatment more difficult further down the line.”

For more information, visit www.environetuk.com