Control of English Hawthorn on Sidney Island

Invasive English hawthorn (Crataegus monogyna) has been identified as a key threat to meadow plant communities on Sidney Island by Parks Canada, the Sidney Island Community, and academic researchers. Management of English hawthorn has been ongoing since 2008 but the English hawthorn population has been progressively expanding into open meadows. English hawthorn shrubs are able to aggressively resprout from untreated stumps and root fragments, rendering traditional control methods of hand pulling or clipping ineffective. Continued English hawthorn invasion will degrade ecosystem health by supplanting native species and changing local environmental conditions to favor shrubs and trees rather than meadow species. An experimental approach is being taken to compare the efficacy of several physical and chemical removal methods in order to determine best practices for English hawthorn control.

English hawthorn shrubs will be cut down using hand saws or power tools (e.g. brush cutters, chainsaws). Garlon brand herbicide will be applied directly to the remaining stumps to control regrowth. Garlon, a triclopyr herbicide, was selected for this trial because it specifically targets broadleaf species, successfully controls resprouting, and has little to no long-term effects on grasses or sedges, as has been documented in peer reviewed academic research. Garlon will be applied in a manner so as to avoid leaching, aerial drift, or surface runoff. The proposed use of Garlon herbicide is consistent with Parks Canada's Integrated Pest Management Plan for Gulf Islands National Park Reserve. Treatment will occur on Sidney Island during March – April and October – December 2020.

Latest update

December 23, 2020 - The assessment decision statement has been issued to the proponent.



Gulf Islands National Park Reserve
2220 Harbour Road
Sidney, British Columbia V8L 2P6
Telephone: 250-654-4000 or 1-866-944-1744
Fax: 250-654-4014

  • Location

    • Gulf Islands National Park Reserve (British Columbia)
  • Nature of Activity

    • Remediation and conservation
  • Assessment Status

  • Start Date

  • Proponent

    Parks Canada
  • Authorities

    • Parks Canada Agency
  • Assessment Type

    Project on federal lands
  • Reference Number


This map is for illustrative purposes. The markers represent the approximate locations based on available data. More than one marker may be identified for a given assessment.


Nearby assessments

...within 200 kilometres
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