Launching during Invasive Species Week, the campaign calls on residents, gardeners, walkers, joggers, families, landowners and voluntary groups to take simple actions this summer to help prevent the spread of Japanese Knotweed and Himalayan Balsam in the Calder Valley.

People can log cases where they see invasive plants on the iRecord app as well as take action by pulling out Himalayan balsam.

People are being asked to only report Japanese Knotweed, not to pull it out, as there is strict legislation around the control and movement of this plant, and it can propagate from small pieces.

Japanese knotweed

Japanese knotweed

Sally Kelling, flood resilience officer with the Environment Agency, who is coordinating the campaign in Calderdale, said:

Invasive species like Himalayan Balsam and Japanese Knotweed have a very negative impact on our environment. It often results in bare river banks in winter increasing the chances of soil erosion, danger of landslides and risks of flooding which is a particular problem for the Calder Valley.

Gavin Roberts, volunteer co-ordinator for Calder Future, said:

It would be great to involve as many local residents in this campaign as possible to make a big hit on invasive Himalayan Balsam in 2021. Areas where local activists have been pulling balsam over the last years have seen a marked improvement and an increase in native flora coming back after the removal of the balsam, so it really is worthwhile continuing this effort. For more information contact

John Cave, project officer for West Yorkshire Wildlife Trust, said:

Yorkshire Wildlife Trust and its partners are taking action to control Japanese knotweed along the river network in Calderdale. We are observing significant impacts to wildlife along many of the watercourses within the catchment, where this plant finds favourable conditions to grow and spread abundantly. Careful management by trained professionals over a number of years is required to control populations effectively.

I encourage Calderdale landowners which have identified issues along a river or watercourse to contact our team for advice about management and support our efforts by submitting sightings of Japanese knotweed to our team by using the iRecord App.

Councillor Scott Patient, Cabinet member for climate change and resilience with Calderdale Council, said:

Last year we reached a lot of people across Calderdale with information about invasive species, this year we hope we can get the support of even more people to report Himalayan Balsam and Japanese Knotweed and help us to manage these damaging plants.

Invasive plants can be spread through soil used by people carrying out renovations or development works to their homes or gardens. It is important to make sure that that any imported soil is certified to be clean of hazardous material including any minute pieces of invasive plant species such as Japanese knotweed. Any material contaminated with invasive plant material must be disposed of at a licenced site not through council refuse collections.

The campaign is being led by organisations working in the Calder Valley including the Environment Agency, Calder Future, Calder Valley Clean-up Team, Calderdale Council, Yorkshire Wildlife Trust, Forus Tree, the Canal and Rivers Trust, Treesponsibility, National Trust, Calder and Colne Rivers Trust, Yorkshire Water, the River Stewardship Company and Slow the Flow.

For advice on managing invasive species safely contact the team at Yorkshire Wildlife Trust at

For more information about invasive species and the action being taken in Calderdale visit

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    Appeal for Calderdale residents to tackle invasive plant species to protect the local environment and reduce flood risk

    by Editor time to read: 2 min