Invasive Species

Worldwide, Invasive Alien Species are the second greatest driver of species extinctions.

Envirico provide a site-specific, best-practice service for the eradication of Invasive Alien Species, including Japanese Knotweed. Explore the different treatment options available by scrolling down or learn how to ID some common Invasive Species by clicking below.

We have strict legislation governing many invasive species in Ireland.

Learn more about the relevance of the Birds and Natural Habitats Directive, and the Wildlife Acts to Invasive Species in Ireland. You can also explore which species are on the current EU's most 'unwanted' list - the List of Union Concern.

Invasive Species Management Plans

If there is a controlled Invasive Species present on your site (as listed in the Third Schedule of the Birds and Natural Habitats Regulations 2011), you have a legal obligation not to allow or cause this species to spread. An Invasive Species Management Plan will ensure that your activities do not cause the invasive species to spread, and will provide evidence that your activities were properly managed to minimise this risk. Any activity on a site where there is a Third Schedule Invasive Species present should be carried out under an Invasive Species Management Plan.

All of our Management Plans are drafted following a walkover site survey and detailed consultation with the client. A GIS trained ecologist will visit your site to carry out the survey. The Management Plan will then be drafted that contains the survey findings and a map of the infestation. Our management plans are tailored to our individual client’s needs, taking into account the treatment objectives, cost implications, future use of the site, timeframe within which works must be completed, and the size and age of the infestation.

Here at Envirico, we are happy to provide a free ID service for you so you can confirm if your suspect species is listed in the Third Schedule, before arranging for a site survey. Just fill in our log form here.

Chemical Treatments

In many cases the invasive species can be best treated by leaving it in its current location and treating it with herbicides over time in order to eradicate it. Herbicides can be applied by foliar spray, direct stem injection, or leaf wiping. Envirico operatives hold recognised qualifications in all of these methods and are registered professional users of pesticides with the Department of Agriculture, Food and the Marine. Some species can be tackled by hand without the need for chemicals. Call us to discuss further.

In-situ treatments are the most cost effective and environmentally sound method for treatment of many species, including Japanese knotweed. However, it can take many years to fully eradicate an established knotweed infestation and time may not allow this option for some sites.


When an invasive species such as Japanese knotweed is present in or adjacent to the footprint of planned construction works, it will require excavation from its current location. If there is sufficient space on the site, the knotweed can be excavated and then moved to an alternative on-site location. Here the excavated material is graded into a shallow bund, and any regrowth that occurs is treated with herbicide over time. Root barrier membranes can be installed at the bund area to provide an additional level of protection for the rest of the site. There may be ecological implications to creating a bund area, which must be fully considered before commencing; however, if a suitable location can be found on-site, bunding provides an excellent and cost-effective alternative to off-site disposal.

Cell & Burial

Invasive species such as Japanese knotweed can be buried on-site in a fully sealed, root barrier membrane cell, if site conditions allow. This method has the advantage that it immediately removes the problem of invasive species from the site, allowing works to proceed without above ground restrictions. Envirico can provide root barrier membrane cells in full-sized, pre-fabricated sheets, minimizing the need for seals. All cells must be buried a minimum of 2m below ground-level.


Screening involves removing viable invasive species vegetation from excavated soil and stones. This is done by sending the material through a screening plant, and hand-picking any small fragments of vegetation off a conveyor belt.  The vegetation can be either incinerated on-site (where permissible under Waste legislation) or removed off-site. The screened material is then spread out into a thin layer, and any regrowth treated with herbicide. This method greatly reduces the time for a herbicide treatment programme to be effective and frees up the site for future development.

Off-Site Disposal

Invasive Species contaminated material may need to be removed off-site to a suitably licenced waste facility. Off-site disposal can only be done under a transport licence from National Parks and Wildlife Service. Envirico can arrange your transport licence and organise licenced hauliers to collect the material and remove it to an appropriate facility for incineration, burial, or export. We can also collect soil samples for Waste Acceptance Criteria (WAC) analysis to determine which facility can accept the waste.

Biosecurity & Root Barriers

Biosecurity is a critical element of working on sites with Invasive Species. Seeds or viable fragments of rhizomes, roots or stems can be easily moved from one section of a site to another if proper biosecurity protocols are not set up. Personnel, plant and equipment will have to be kept clean and follow set-routes to ensure they do not spread invasive species to other sections of the site or off-site. Envirico have specialist equipment including a biosecurity unit for personnel, ground guards, and geotextiles that will ensure that no spread occurs during your works.

Root barrier membranes can be deployed to ensure that your site or structure is protected from invasive species into the future. We provide root barriers that are guaranteed impenetrable by Japanese Knotweed in pre-fabricated sizes manufactured to specification for your site. Root barriers can be installed around a perimeter to protect against potential re-introduction, underneath road surfaces, wrapped around foundations or used to create cells for burial.