Japanese knotweed warning issued after first shoots of the year spotted in Devon

Homeowners in the South West are being warned to look out for Japanese knotweed after the first shoots of 2022 were spotted in Plymouth. The invasive plant has emerged on the banks of the river Plym two weeks earlier than last year.

As we head into spring, we're out in the garden more often, bringing garden ideas to life. Keep an eye out for this nightmare plant.

Japanese knotweed warning

'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,' says Emily Grant, Environet’s Regional Director for the South West. 'Those who discover Japanese knotweed on their land should seek professional advice.

She says a professional treatment plant is the best way to go. This will 'prevent knotweed from causing damage to property, preserve the value of your home, and protect yourself from the threat of litigation from neighbours if it’s allowed to spread.'

Japanese knotweed's first sighting in 2022

Emily comments that just a few years ago, it was totally unheard of for Japanese knotweed shoots to emerge in February or March. 'Unfortunately, this now seems to be the norm.'

She says that the warmer climate in the South West certainly helps Japanese knotweed along, with the UK’s first shoots spotted in Plymouth for the second year in a row.

Japanese knotweed is the most invasive plant species in the UK. The first sighting of it this year shows the plant has already begun its spring growth season, after hibernating through winter.

In previous years, it was first spotted at the end of March and in early April. Possibly due to climate change, it's now appearing earlier.

Typically, it begins to emerge when ground temperatures reach 4 degrees Celsius. A red or purple shoot like the one above can grow rapidly.

It can transform into a 3 metre-high bamboo-like stem in three months. Japanese knotweed grows flat, heart-shaped leaves and blooms with white flowers in late summer.

If you spot something that looks like Japanese knotweed, you can email a photo to expert@environetuk.com. Environet will identify it for you for free. The rapidly growing plant is often mistaken for bindweed, Russian vine and lilac. Better to be safe than sorry.