Japanese knotweed on New River path

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Permalink Reply by Hugh on May 8, 2025 at 22:52

As I understand the situation, it is the landowner who is responsible for controlling the spread of Japanese Knotweed. When I need to contact Thames water, I use customer.feedback@thameswater.co.uk.

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Permalink Reply by David Thomas on May 9, 2025 at 0:17

There is also a large clump on the bank ( right hand side going up) on Umfreville Road . Reported it to Thames( hard work) who passed the buck saying it was council responsibility-which of course is not the case. The clump has grown since last year and about 2 metres from the side of a house. I know the issue of knotweed has been ‘ downgraded’ recently but still should be addressed .

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Permalink Reply by Jonas on May 9, 2025 at 8:46

Thanks for that information.

I did not know that the hazard had been downgraded. If I had I probably would not have bothered to even attempt to contact Haringey, let alone Thames water.

Here is a quick AI generated summary of the current situation: 

The perceived hazard of Japanese knotweed has been downgraded in London and the UK, according to new guidance from the Royal Institution of Chartered Surveyors (RICS). The RICS, which governs building surveyors, now states that knotweed should not affect a property's value unless it's causing visible damage. This shift in guidance is based on the understanding that the plant's impact on robust structures is minimal, and that focus should be on its impact on amenity value and potential damage to less sturdy structures. 

Here's a more detailed explanation:

Revised Risk Assessment:

The RICS has moved away from a strict "seven-meter rule" (which suggested a mortgage might be refused if knotweed was within seven meters of a property boundary). Instead, surveyors are now encouraged to use their professional judgment to assess the potential impact of knotweed, considering factors like the type of structure and its foundation. 

Focus on Amenity Value:

The new guidance acknowledges that knotweed can affect the enjoyment of a property's garden and other amenities, even if it doesn't pose a structural threat to the house itself. 

Impact on Specific Structures:

While a house with substantial foundations is generally considered safe, Japanese knotweed can still be problematic for less robust structures like garages, conservatories, and boundary walls. 

Control vs. Eradication:

1. The new guidelines suggest that controlling knotweed rather than eradication might be a more realistic approach, especially for well-maintained properties. 

Legal Considerations:

It's important to remember that while there's no legal requirement to remove Japanese knotweed, it's crucial to prevent its spread onto neighboring properties. 

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Permalink Reply by Felicity Ford on May 12, 2025 at 8:48

There is really useful information on the control of knotweed here https://www.gov.uk/guidance/prevent-the-spread-of-harmful-invasive-...

It says clearly it is illegal to permit it to spread. In the past we had to report it to the Environment Agency (on allotment land). There are very clear instructions for the removal and destruction on the site.

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Permalink Reply by Cowper on May 13, 2025 at 10:57

Hi all;  This morning, Tue 13 May, I talked to the company that will be cutting back the bushes along the New River Path in the next few days.  This is something that I have been working for about a year and a half.  In our conversation, one of the men mentioned that they do spraying.  Given that, I mentioned the Japanese Knotweed to the them.  They saw it and pointed it out to me.  So, hopefully that will be dealt with too.  Given the work they have to do, the path will probably be shut for a few days.  

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