Alert over discovery of Japanese knotweed
INVASIVE and devastating perennial plant Japanese knotweed has been spotted in Plymouth, environment experts say.
The plant, often labelled as one of the UK’s most invasive plant species, has spread rapidly across Devon and the wider South West in recent years and can cause a serious problem for roadsides and riverbanks and increasingly, gardens and residential areas.
While the plant is not harmful to humans, unlike Giant Hogweed, Japanese knotweed is seen as dangerous as it can cause significant damage to its surrounding environment, which can be very expensive to clear up.
The first Japanese knotweed shoots of this year have been located on the banks of the River Plym in Plymbridge Woods.
Emily Grant, South West regional director for plant specialists Environet UK said: “We’ve been on the lookout for the first knotweed shoots for a few weeks, but this cluster spotted on the banks of the River Plym are the first we’ve seen or heard of in 2021.
“Homeowners across Devon and Cornwall should be vigilant for the distinctive red or purple spear-like shoots emerging in their gardens or near their homes over the next few weeks, as the knotweed growing season becomes established.
“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 to protect themselves from the risk of litigation if the plant is allowed to spread.”
Japanese Knotweed is the UK’s “most invasive and destructive plant,” according to Environet UK.
The plant typically hibernates through the winter months, before emerging when the ground temperature reaches around 4C, usually in March or April.
Japanese Knotweed consists of asparagus-like red or purple shoots sprouting from the earth. The shoots develop into green bamboo-like stems and can reach three metres in height.
The plant can wreak havoc on the foundations of houses, as well as on driveways, patios, cavity walls and drains - impacting around 5% of UK homes and often knocking up to 10% off house prices. Sightings can be logged online on Environet’s ‘Japanese knotweed heatmap’ called Exposed.