Invasive Non-native Plant Species

The three invasive non-native plant species causing the most issues to the construction and development industry, public access and native habitats are Japanese knotweed (Fallopia japonica), Himalayan balsam (Impatiens glandulifera) and giant hogweed (Heracleum mantegazzianum).  Introduced as decorative plants in the 1800s, they have escaped out of parks and gardens and successfully spread across Britain, encouraged by a lack of natural enemies, and aided by water courses.  They are found along river banks, railway lines, allotments, in waste land and derelict sites.  For more information on invasive non-native species, please see the identification sheets here. 

It is an offence to plant a non-native species in the wild, or allow them to spread into natural habitats.

Surveying

As part of the Preliminary Ecological Appraisal we inspect the survey area for all non-native plant species (i.e. our survey is not restricted to just the three species mentioned above).  Our surveyors are experienced in recognising and identifying the plants and we offer advice on best practices for control and removal of the invasive species, in line with the Code of Practice on Non-Native Species, as outlined by the Scottish Government.  For more information on the Code of Practice, please visit this website. 

Control and Removal

Currently the control and eradication of invasive species involves strategies such as physical removal by cutting/ pulling or digging out of the plants, as well as chemical control, with the weeds being sprayed or injected with appropriate weed-killers.

There is also ongoing research into the biological control of Himalayan balsam and Japanese knotweed, as undertaken by CABI (Centre for Agriculture and Bioscience International). For more details on the research and the trials carried out within UK, please see https://www.cabi.org/projects/project/32999 and https://www.cabi.org/projects/project/32944.

Ecological Clerk of Works

We have experience in supervising works within contaminated sites, to contain the invasive species and prevent the spread outside the site.  As part of the supervision programme we can produce and deliver a Toolbox Talk, provide a Method Statement for containing and/or eradicating the invasive species and supervise the implementation of the Method Statement.

Please note: we do not carry out the physical removal or treatment of the invasive plant species ourselves.