Friday, 12 July 2019

Return of the Triffids

It has become a subject of polite but anxious conversation amongst homeowners that has replaced the old mainstays of dry rot, mould, property values and school catchment areas.

Whether conversations are had over the garden fence, in the pub, coffee shop or in the old fashioned way at a dinner party they will, without fail, turn to the subject of Japanese Knotweed.

I have written before on the origins and wildfire spread of this plant species which was introduced by the Victorians as an attractive, Himalayan foothills bit of planting for a conservatory, urban or country setting. It was a popular bit of vegetation in the 19th Century with its willowy, bamboo-ey stems with red speckles and broad veined leaves. Its spring emergence in flower beds and borders resembled rhubarb shoots and indeed upon the realisation that the young growths could be eaten it became known colloquially as Donkey Rhubarb.



Other prettier ornamental trees and shrubs soon pushed Japanese Knotweed into obscurity and many would have expected that it would die off and disappear into remote pockets.

In fact it continued to thrive on industrial wastelands, building clearance sites and on railway embankments and by the sides of canals seeking space and nutrition at the expense of all other competitors.

It did not get much publicity in the UK until the run-up to the London Olympics when vast tracts of land earmarked for the infrastructure and iconic arenas and Games Village were found to be firmly in the grip of this virulent, invasive species. Natural evolution had made it highly resistant to herbicides and other chemicals. A slash and burn approach to clearance only served to highlight the prolific ability of the plant to germinate from any fragment making it virtually impossible to destroy.

If buried under concrete as in foundations or ground slabs the relentless survival instinct allowed knotweed to simply penetrate through to reach sunlight and rain. The Olympic sites required multi-million pound expenditure on a clean up scheme which delayed the schedule to a significant extent.

Publicity in the media and a bit of a paranoia amongst homeowners looking out over their own gardens put the species firmly in the perception of the public as something very nasty and hellishly expensive to get rid of.

There is lot of the particular plant in my local area being characterised by favoured habitats such as active and disused railways on raised courses through the city and a large student population who have no interest whatsoever in that huge green growths in the back yard of their shared house accommodation which seems to be getting closer and closer at an alarming rate.



The well-to-do avenues on the fringes of the inner city, once the prime residential location for an emerging middle and entreprenurial class over 100 years ago, began a hate campaign against Japanese Knotweed after a few very unwelcome outbreaks in back gardens.

Leaflets were distributed to homes and every other lamp post carried a sobering warning of attack with a grainy black and white photograph illustrating a typical offending growth.

One hapless resident panicked upon a discovery amongst his rhododendrons and promptly dealt with it by ploughing up and down with a hired mechanical rotovator. This was the worst action possible given the ability of Knotweed to sprout new growths from the smallest splinters and fragments.

I was passing a few minutes today with a local in the avenues area who happened to be a maintenance gardener for the University.

He had recently been called upon by his Manager to attend at a student house close to the main campus upon reports that the dreaded Knotweed had been spotted.

The forecourt to the street was a bit overgrown and littered but clear of any rampant vegetation. In the rear yard, accessible through a shared covered passage in the terraced block, there was a mass of foliage but all fairly tame and placid.

A quick peep over the fence into the flanking properties did not indicate any outbreaks.

It appeared to have been a wasted journey caused by mis-identification or even a hoax.

Knocking at the back door to try to get more information from a student who was, with bleary eyes, in the kitchen making a cup of tea the gardener noticed a bit of greenery sticking out through the cabinet doors below the sink and drainer.

The student, in filling up the electric kettle carefully negotiated the growth and although the size of a small tree it did not obstruct this process. A few further journeys to the fridge for milk, pantry for bread and a top storage unit for Marmite spread saw a repetition of the strange waltzing movement of man in relation to the plant.

It was definitely of the Knotweed genus and quite at home in this warm, humid environment which must have closely resembled the foothills of Tibet and Nepal especially when all of the windows were shut, cooker and hob in use and extractor fan left switched off.

Why it had not been reported was a mystery but then again it appeared to be able to peacefully co-exist with lazy and messy students quite nicely.

Investigation revealed that the main stem originated from the pipework at the very back of  the sink unit. A plumber was called out and in dismantling the services it was clear that the plant had come in by following the underground waste pipe system from some considerable distance beyond the immediate boundary.

It took a good deal of effort and expense to remove the alien intruder.

For a few weeks afterwards the students in residence continued to take a roundabout route to the kitchen taps as though somehow indoctrinated and under the influence of the all-pervasive invasive species.

No comments: