Have You Got Japanese Knotweed?

Published on: 20 Apr, 2015
Updated on: 20 Apr, 2015

Japanese knotweed – Have you seen this plant?

A mild winter and early spring has created ideal growing conditions for the dreaded Japanese knotweed – one of the most invasive plants in the UK.

Commercial property specialists at Bruton Knowles’ Guildford office is already receiving calls about the nuisance species – which can spread at more than a metre a month.

Associate Naomi Quick said: “Japanese knotweed can be a nightmare for homeowners and developers causing unbelievable amounts of damage to drains and other buried services, paths and driveways, boundary/retaining walls, outbuildings as well as homes, conservatories and gardens.

“We always get a number of calls from worried owners but the alarm bells are ringing much earlier this year – even on sites we know have already been treated.”

The potential cost of removing the plant from the UK as a whole has been estimated at £1.25 billion.

The Royal Horticultural Society estimated that the cost of removing and disposing of Japanese knotweed during preparation work for the Olympic park in East London hit £70 million.

Naomi Game, Bruton Knowles Guildford

Naomi Quick said removal requires a specialist contractor to treat the plant. Simply applying herbicide is not affective.

She said: “There are optimum treatment times for different chemicals. Japanese knotweed is an unpredictable plant but in the majority of cases the problem can be eliminated within 18 months although often a 3 to 5 year program of treatment is required to ensure eradication. You therefore need to be very patient!

“Due to the potential disruption this plant can cause, some lenders are now reluctant to lend on properties that has the plant present unless there is commitment from the owner to treat and remove the plant.

“Japanese knotweed is incredibly persistent and cannot simply be pulled up, chopped down or subjected to heavyweight chemical attack. Homeowners will ignore this menace at their peril.”

The weed is known to have invaded the site of the old CEGB offices at the bottom of the Portsmouth Road. Treatment is understood to have commenced six months ago.