Inquiry into the impact of Japanese Knotweed on the built environment.
The Science and Technology Committee are holding an oral
evidence session in early 2019,
specifically to explore the science behind the effects of Japanese
Knotweed on the built
environment. To inform that session, written submissions were
invited and the Amenity Forum has
made a response.

The Amenity Forum welcomed the inquiry. Whilst there has been
research and studies on the topic, it is felt more is needed if we
are to fully understand the impact and implications. There has been
a number of studies observing specific sites where structural
damage has been caused but it is felt that more scientific studies
are very much required. The Forum also feels that more economic
analysis is needed and indeed is vital to establish the financial
implications now and in the future. This would assist Government
greatly in establishing both its strategy and future plans to
combat the issue. It is undoubtedly the case that the presence of
Japanese knotweed rhizome within a construction, if left unchecked,
can produce significant damage especially within masonry and hard
surfaces.
The Forum also states that what has already emerged, in looking at
the range of controls, is the importance of chemical products
including those with the active ingredient, glyphosate. Whatever
approach has been trialled, chemical treatment remains extremely
important and provides the most effective approach in any
integrated plan for knotweed management. They go on to say knotweed
management is a long term plan and cannot be seen as a quick fix.
Clearly it can be controlled by treatments but the point at which
such a treatment plan is complete remains uncertain. There would
appear to be a need for more research and examination of the
rhizome that remains following professional treatment. Establishing
the facts relating to the viability of that material when disturbed
is key to establishing protocols for sites that have been subjected
to a treatment programme.
Professor John Moverley, Chairman of the Amenity Forum, very much
welcomed the focus on this topic and emphasised the need to use
professionally trained operatives in managing the problem. He said
''What is vital is that knotweed control needs to be undertaken
properly and by professionally qualified operators and
organisations who fully subscribe to the standards and best
practice laid down. The Amenity Forum is currently developing an
overarching assurance standard for the sector and we would urge all
employing any operators to ensure that they can deliver to such a
standard and, in so doing, fully support the work and objectives of
the Amenity Forum. Bad practice and unqualified operators can make
the situation far worse and sadly there is evidence of such
practices existing. The need for assured practice and the need for
users such as local authorities to adopt these is vital''
The Amenity Forum is holding a series of half day Updating Events
across the UK over the coming months. These are free to attend and
will update those attending on current issues and concerns.There
will be time for questions and essential networking.