Japanese knotweed warning for homeowners as pest appears early thanks to warmer than average February

7 March 2019

Homeowners are being warned that the unreasonably warm weather in February has prompted the emergence of Japanese knotweed one month earlier than usual.

If you don’t recognise this invasive plant, it can damage your property as well as your neighbours. It can also cause property sales to fall through if knotweed is only recognised when buyers arrange a survey.

Japanese knotweed removal firm Environet says it spotted spring shoots of Japanese knotweed last week in North Devon.

Image courtesy of Environet

Japanese knotweed hibernates during the winter and starts to grow when the ground temperature reaches around 4°c, usually in late March or early April.

However, the warm weather which averaged 10°c and peaked at 20.6°c in West Wales at end of February has resulted in knotweed to emerge early from its winter slumber.

Environmental scientist Nic Seal, managing director of Environet, says: “In twenty years of operation, I’ve never seen Japanese knotweed appear in February.

"The unseasonably warm weather has awakened the plant from its winter hibernation and prompted it to start growing an entire month earlier than normal. We’re gearing up for an early start to our treatment season to give our customers maximum protection from this highly invasive plant.

“Those who discover knotweed on their land should seek professional advice. They will probably need to put a professional treatment plan in place to protect their property and themselves from the threat of litigation from their neighbours.”

The knotweed has emerged a whole two months earlier than last year, when it was delayed due to the 'Beast from the East' and didn’t appear until the end of April and into May.

It can be spotted by the red or purple asparagus-like shoots (see below) that sprout from the ground and quickly grow into green bamboo-like stems. It grows at a rapid rate of up to four inches a day and if left unchecked could even knock 10% off your house price.

Image courtesy of Environet

Environet offers a free Japanese knotweed identification service where homeowners who are worried about a plant can send a photograph for review. If knotweed is identified and a homeowner wants a quote, it will be provided - but the company says there is no obligation.


In reply to by anonymous_stub (not verified)

Apparently, at one time, because it was so quick growing, it was used to stabilise railway sidings from soil erosion so it may be as well to double check if you are near the railway.

In reply to by anonymous_stub (not verified)

This is a promotional article for the firm charging a fortune to remove Japanese knotweed. Recent studies by Leeds University show that the damage caused by the knotweed is not as severe as the removal industry would have us believe. This is the same kind of hype that the bottled water companies used to launch the water drinking craze leaving us with a plastic pollution problem with all the discarded bottles.

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