The Japanese knotweed hotspots in Wiltshire have been revealed, according to data from the Environet heatmap.

Homeowners who are spending more time in their gardens during lockdown might be shocked to discover Japanese knotweed as it enters its spring growth phase.

According to the knotweed experts’ live records, Chippenham has 10 infestations within 4km.

In Warminster, there are six recorded infestations, while Pewsey and Bromham both have four within the same threshold.

Described by the Environment Agency as “indisputably the UK’s most aggressive, destructive and invasive plant”, Japanese knotweed grows rampantly along railways, waterways, in parks and gardens and is notoriously difficult to treat without professional help.

It can reduce a property’s value by around 10 per cent and make it difficult to sell unless a treatment plan is in place with an insurance-backed guarantee, which will satisfy mortgage lenders.

Homeowners who discover the plant can report it on Exposed using the ‘add sighting’ feature, uploading a photo for verification by experts.

According to Environet UK, approximately 4 to 5 per cent of the UK’s houses are currently affected, either directly or indirectly (e.g. neighbouring a property where it’s present) but despite the plant’s fearsome reputation, homeowners should not panic if they find themselves in lockdown with this unwelcome guest.

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.

“In most cases knotweed can still be removed during the lockdown period, but if this isn’t possible it won’t make a huge amount of difference to leave the plant growing until restrictions are lifted.

“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.

“Where we cannot treat or remove knotweed due to current covid-19 restrictions, we pledge to tackle at no further cost any resulting spread on clients’ property.”