As we start a new year, I thought it might be worth re-visiting why the Invasive Non Native Specialists Association (INNSA) was originally founded.

Going back twenty years or so, invasive species had become an area for concern and Japanese knotweed in particular had captured the public imagination. Newspaper articles about devalued properties and damage caused by this aggressive invader were appearing regularly and demonised the plant to the point of creating dread amongst homeowners and housebuilders alike.

My personal involvement with Japanese knotweed began in the 1990’s, when I owned and managed both a landscape architectural practice and a landscape design and build company. When Japanese knotweed was found on projects I was working on, I was asked to come up with remediation strategies. The skill sets and teams from my landscaping companies were ideal for comprehensive survey work and the follow-up chemical or physical removal treatment prescribed.

Information at that time was very difficult to find, with one or two go-to experts being the people to call. I quickly realised that there was a market for a company able to manage the problem, and I set up Japanese Knotweed Solutions Ltd, the first company dedicated to offering management solutions for a single plant species.

Other companies rapidly came into the market, mainly from grounds maintenance or landscape background – and the beginnings of an industry were born.

At this time if one were to ask for a quote for Japanese knotweed removal one would be hit with a wide range of responses. Options and recommendations differed wildly from those promising ‘instant eradication’ and ‘single application’ herbicide solutions to those offering removal from site and ‘guaranteed clean site’.

The prices for these different strategies would be wildly divergent, ranging from a few hundred pounds to tens of thousands; the major downside was that in most instances neither of these options worked.

Customers who wanted excavation did not want to hear the truth – which was that nobody could really tell how far the plant had spread until they had started to dig – so a fixed price lump sum was very difficult to provide.

With chemical treatment, customers wanted to know ‘what day’ the plant would be dead. This was just an impossible question to answer as treatment programmes require repeat visits to site and vary depending upon weather conditions, ground conditions and how well established the plant was.

Over the years – and particularly in the early 2010’s, once mortgage lenders started to restrict funding on properties affected by Japanese knotweed – many contractors gained advantage by suggesting that they had a ‘secret chemical formula’ that nobody else had or unique ‘Lloyds backed insurance warranties’ – all of this wrapped up in jargon so complicated that nobody knew what it meant.

Confusion was the order of the day for a period of about twelve months, where consumers had idea who was doing things correctly and who might be running some sort of “racket”.

It was during this period that several major players in the industry banded together to set up a trade body that could oversee operations and make rules that all of them would follow. So it was that INNSA came into being. This was the birth of the new age where each project would be quoted on the same level playing field and where clients would have the ability to reliably compare one quote to another.

The original concept of providing a code of practice to continue the legacy of the (now withdrawn) EA Code of Practice is still held dear by any INNSA member and, with our system of monitoring and checking that all companies within the INNSA group maintain insurances and carry out all works within the guidelines quoted, the highest of standards will be maintained.

However, INNSA must continue its work addressing issues in the industry, which, while somewhat improved, still has its problems. Particular problems for today’s clients stem from companies carrying out poor or misleading surveys.

Some companies now seem to delegate the task of carrying out site surveys and producing detailed site reports to site-based spray operatives who are untrained in survey work. Whilst this may save money on the cost of employing environmentally-savvy, competent surveyors, it does nothing for the reputation of the company and damages the industry by presenting invasive plant specialists as unskilled amateurs or simple grounds-maintenance contractors.

Other reports include contractors either “missing” large areas of the plant on their survey and putting in a low price, or submitting re-measurable prices based on questionable estimates of the underground extent of the plant’s rhizome (which is much better understood nowadays, due to extensive industry experience, but still requires further research, in INNSA’s opinion). Once appointed based on their seemingly cost-effective quote, the contractor “finds” new areas not previously noted or discover that the rhizome extends further than they allowed for in their estimates, and look to charge the client significant additional fees.

Clients can protect themselves from this is to commission surveys from a company registered with a recognised trade association, who employs trained, dedicated surveyors. This can help to identify where one contractor may be relying on creative underestimation to increase their profits once the client is already on the hook.

It may seem like an attractive option to get a “free survey” from an unregistered company, and to ask for three quotes based on their report but, in fact, the option likely to produce the most accurate and reliable quotes – which could save a lot of money in the long term – is to make full use of the competent surveys, ask questions and compare what is on offer. If one company offers something that others don’t, ask them why… if one company seems to think that you can dig out one metre around the plant and to a depth of 300mm, yet others recommend a three metre radius and a depth of 500-1,500mm, focus on what will happen to your costs if the smaller quote ends up needing greater volume in order to remove all the material.

While issues such as these continue to plague the industry, there will always be a place for INNSA and we shall continue to strive for the highest of standards.


Mike Clough