Warning over UK's 'most invasive' plant spotted in Greater Manchester town which could land you in trouble

A warning has been issued to homeowners after signs of the UK’s ‘most invasive’ plant have been spotted in Greater Manchester. The first Japanese knotweed shoots to be seen this year by Environet, the national invasive plant specialist, have been spotted in Stockport.

According to the experts, Japanese knotweed has begun its 2024 growing season, with distinctive red, asparagus-like shoots having emerged on banks of the River Goyt. Stockport is reportedly home to 122 verified infestations of knotweed, according to Exposed, Environet’s live heatmap which is populated with over 50,000 known sightings across the UK.

Described as the UK’s ‘most invasive plant’, Japanese knotweed can damage properties, driveways, patios and drains, impacting around five percent of UK homes either directly or through adjoining an affected property. If knotweed is present, it must be declared when a property is sold.

It can also be extremely difficult and costly to remove, and could devalue your home. In the worst cases, it can knock five to 10 percent off house prices and cause legal disputes between neighbours.

Japanese knotweed hibernates during the winter months, before emerging when the ground temperature reaches around 4°c, usually between late February and early April. Red or purple asparagus-like shoots sprout from the earth and quickly turn into green bamboo-like stems, growing at a rapid rate to reach approximately 3 metres in height by June.

Nic Seal, founder of Environet, said: “Knotweed has appeared quite early this year, due to recent mild temperatures. Fifteen years ago, we never spotted it until April, but possibly due to climate change knotweed and other perennial plants are waking from their winter hibernation in February.

What Japanese knotweed looks like once grown

“There are already over 50,000 known infestations of knotweed and the number is growing every year. Now it’s been spotted and verified in Stockport, within a week or two it will be emerging all over the country as the spring growing season gets underway. Those who discover the plant on their land should seek professional advice and put a treatment plan in place as quickly as possible, to preserve the value of their property and protect themselves from the risk of litigation if it’s allowed to spread.”

Environet offers a free identification service for anyone who is unsure whether a plant is Japanese knotweed, which is commonly mistaken for other harmless garden plants such as bindweed, Russian vine and lilac. Just email a photo to [email protected].

How to spot Japanese knotweed in early spring:

• Soft, dark red shoots emerge from the ground, which look similar to asparagus
• Leaves are rolled up to begin with, and dark red/purple in colour
• The stems resemble bamboo canes, but with distinctive purple speckles
• As the fleshy shoots gain height, usually around early April, they develop bright shield or heart-shaped green leaves which unfurl in a zig-zag pattern along the stem
• When the warm weather arrives, knotweed can grow rapidly, at up to 10cm per day.