BURLINGTON— Using an innovative new technique, utilized for the first time at this scale in Ontario, Conservation Halton (CH) is seeing the fruits of its labour this spring, after successfully managing 1,820 m² of Giant Hogweed (approximately 11,000 stems) in the Boyne Sixteen Mile Creek lands in Milton last summer.

CH is working in partnership on a ten-year project with the Milton Phase 3 Landowners Group—comprised of 19 community developers—as project managers for the restoration of key natural heritage features and functions in the Boyne valley lands. Upon completion, these lands will be dedicated to the Town of Milton.

“The removal of Giant Hogweed and restoration of the Boyne lands is an innovative example of collaboration between a conservation authority and community developers. Utilizing nature-based solutions we are building more resilient ecosystems and protecting public safety, all while saving both time and money,” said Hassaan Basit, president and CEO, Conservation Halton.

Giant Hogweed is an invasive plant that is a safety concern to the public due to the toxic properties of its sap that can cause severe burns and blisters to skin. As Boyne undergoes residential development, there was a significant risk that Giant Hogweed would pose a public safety threat as plants were moving closer to the planned Natural Heritage System trails system and residential backyards.

Ordinarily, Giant Hogweed is managed by an ongoing program of spraying herbicide over a three-to-five-year period, followed by restoration work to replace the invasive plant and ensure soil stability. Utilizing new techniques, in seven days, CH removed the Giant Hogweed and then dug a 50 cm deep trench into the base of the slope where both the Hogweed soil and seedbank were buried and will not be able to germinate. After the Giant Hogweed was removed in August 2020, a mix of soil, seed, and stabilizers were used to ensure slope stability and the return of native species. The treated area and surrounding restoration resulted in 2,600 m2 of restored land.

“By using this innovative on-site nature-based solution, CH sped up the restoration of this portion of the Boyne valley slope by 5 years and reduced the use of herbicides by 99%,” said Nigel Finney, project manager, Conservation Halton “While this approach is highly effective, it is not practical for many locations where the species is invading. This approach was possible in Boyne because the project area was not covered in native trees and shrubs, machinery access was feasible from an old farm lane, and there was an open floodplain field to bury the seedbank nearby.”

“Continued coordination with regulatory agencies such as Conservation Halton is imperative through development processes. Application of effective solutions to address legitimate safety concerns ensures safer communities for all stakeholders,” said the Milton Phase 3 Landowners Group.

Throughout the remaining restoration projects in the valley, CH will manage the Giant Hogweed providing safe workspace for workers and increasing canopy cover of native species to reduce the available habitat for Giant Hogweed. Upon full completion of remaining restoration efforts, the land will be transferred to the Town of Milton as protected greenspace.

before and after images of the work done to reduce giant hogweed habitat

Quick Facts

  • CH treated and restored total of 2,600 m²—the equivalent of a 105-car parking lot.
  • If not removed, each Giant Hogweed plant can produce up to 50,000 seeds per flower head and remain viable in the seedbank for 15 years.
  • The project removed an annual spread of 550 million Giant Hogweed seeds at the site.
  • The project was permitted and regulated under the Conservation Authorities Act and registered under the Endangered Species Act and was reviewed by the Town of Milton.


Conservation Halton is the community based environmental agency that protects, restores, and manages the natural resources in its watershed. The organization has staff that includes ecologists, land use planners, engineers, foresters and educators, along with a network of volunteers, who are guided by a Board of Directors comprised of municipally elected and appointed citizens. Conservation Halton is recognized for its stewardship of creeks, forests and Niagara Escarpment lands through science-based programs and services.

Media Contacts:

Stephanie Bright
Public Relations Specialist
Conservation Halton
Email: sbright@hrca.on.ca
Milton Phase 3

Landowners Group Contact:
Chris Lant
Project Manager
Delta Urban
Email: chrisl@deltaurban.com