Homeowners across Berkshire spending more time in their gardens are becoming worried by the appearance of the highly invasive Japanese knotweed.

Described by the Environment Agency as 'indisputably the UK’s most aggressive, destructive and invasive plant' it 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.

The appearance of red, asparagus-like shoots at this stage of the spring indicates that there is a problem.

Reading, Windsor, Slough, Maidenhead and Wokingham have all been identified as hotspots - with 45 infestations identified in Reading, 37 in Windsor, 33 in Slough, 13 in Maidenhead and 10 in Wokingham.

Homeowners in these locations should be vigilant during April when knotweed starts to grow rapidly, turning from red to green before forming hollow bamboo-like canes. By late spring it is covered in attractive heart-shaped green leaves.

Nic Seal, founder and MD of knotweed specialists 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."