Japanese Knotweed Eradication

Japanese Knotweed | 02nd March 2018

Japanese knotweed Eradication, Extermination, Elimination, Obliteration, Annihilation, Extinction! – whatever you call it, can it be done?


This week there was a very telling article on the BBC News Website entitled “Knotweed ‘cannot be eradicated’, Swansea Uni trial shows”. But the headline belied the actual quote further down the article which qualified this statement.

At PBA Solutions we have been successfully treating Japanese knotweed for over 20 years and have expert and intimate knowledge of the plant and its ways. One of the points we make to our customers is that eradication is almost impossible to confirm. This is why we take the long view of treatment and management to get the infestation into a state of dormancy and decay. You just never know when that last remaining centimetre of rhizome has finally died. So at PBA we call it Japanese knotweed control, not eradication. We help our customers to understand that it is a process of control that leads to knotweed decay and eventually eradication.

Because of this we advise that there cannot be a change to land use where Japanese knotweed is being treated and managed. Customers ask us when JK will be eradicated but as there is no way of knowing when this will be, we cannot give a definitive answer. This is why we recommend a 3-5 year treatment programme to control and eliminate growth, followed by monitoring until no growth is present for 2 years, and then offer a 10 year guarantee that it won’t re-emerge, and if it does we will treat it for free. During this time we recommend that the land is not disturbed, or if this is required then a consultant is involved to minimise the risk of re-emergence.

Sadly, we recently had one customer on our management programme who decided to get landscapers in without telling us during the guarantee period. The landscapers did not regard the fact that there was a history of Japanese knotweed there as it had not been visible for a couple of years. The following year the Japanese knotweed was back. The owners were mortified as they had invalidating their 10 guarantee by their actions, and they promised not to disturb the ground like that again. The management plan had to go back to the beginning again.

Professionally designed management programmes with a treatment regimen have proven to be effective over the long term. Backed up by detailed case history documentation, they place owners in a strong position if they are challenged by neighbours in relation Japanese knotweed. As in the case of the Williams vs Network Rail case it was demonstrated that unmanaged Japanese knotweed that spreads to neighbouring property can lead to diminution of property value.

The Williams vs Network Rail case shows there is a new paradigm relating to the long term repercussions of Japanese knotweed presence. This case helps to illustrate why it is very important that a proper management plan is in place backed up with thorough documentation, including records of all treatments and monitoring visits. Additional monitoring during the guarantee period can show that due diligence has been taken and will act to protect the owners of impacted land should any legal challenges arise.

At PBA Solutions we tailor our management plans to suit the specific scenario we discover when we conduct a knotweed survey at a property, or commercial site. In the main this comprises of 5 years treatment and monitoring and then a 10 year insurance backed guarantee. This means that a 15 year supportive relationship is anticipated with the customer. PBA Solutions uniquely offer a Client Account arrangement to reassure the customer that their funds and treatment programme is secured. As PBA are a highly credit rated company with good financial credentials, we can provide peace of mind to our customers for the long term.

We think the PBA Solutions standard far exceeds the industry norm.

So going back to the BBC News item, what Prof Dan Eastwood from the project actually said was “Off the back of the first three years of data we’ve found that eradication is not possible.” And we would agree with this statement. If you are looking to get your Japanese knotweed treated beware of those who claim otherwise.

You can call us on 01202 816134 to discuss your situation and we will be happy to provide advice and an estimate for the professional treatment and management of your Japanese knotweed.

The full BBC article can be accessed here: Knotweed ‘cannot be eradicated’, Swansea Uni trial shows

You may also be interested to read our document: Japanese knotweed Advice Note

Fiona Aucott 30 April 2018


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