Invasive Species Management


Managing invasive species

Invasive plants and animals threaten ecosystem health by displacing native plant and animal communities, making the ecosystem less diverse. Outdoor recreation, property values, and timber and agriculture production can also be negatively impacted by invasive species. Invasive species can also be harmful to people and animals. Therefore, it’s worth the effort to control or prevent the spread of such species.

There are many benefits to managing invasive species:

  • Reduce risk of erosion and improve water quality

    A monocultureMonoculture A single type of plant growing in an area. of invasive plants has a much less diverse network of roots compared to several different kinds of native plants that will grow together in a healthy ecosystem. Diverse native plant root systems hold soil in place and reduce sedimentationSedimentation Fine soil particles that are washed into streams collect at the bottom and make water cloudy of waterways.

  • Reduce risk of wildfire

    Fire will “climb” up ivy-covered trees and catch the tree crown on fire, which will likely kill the tree and more easily spread to other trees. Dense patches of blackberry are highly flammable and can also help carry fire into a tree canopy.

  • Improve wildlife habitat

    Native wildlife depend on a rich and diverse ecosystem of native plants and animals.

  • Improve the look of a landscape

    A diversity of beneficial plants growing in suitable locations creates a beautiful natural setting.

  • Increase land and property value

    Land free from weeds is better suited for livestock. Properties free from weeds are more attractive to buyers.

On this page:

    Discover more:

    • Check

      We can help you determine whether you have a high priority weed. See this list of common invasive plants in Portland.

      Check out our resources
    • Ask us

      We can answer your questions about controlling invasive weeds on your property.

    • Treat

      We will directly treat high priority Early Detection Rapid Response (EDRR) weeds on your property.

      Learn more about EDRR weeds
    • Manage

      We can help you develop a conservation plan or active restoration project, which can lead to help with managing more common invasive weeds such as English ivy, reed canary grass, and Armenian blackberry.

    Priority focus

    Early Detection Rapid Response (EDRR)


    We locate and manage high risk invasive weeds before they can become established in our region. We target species that pose the greatest risk to our local ecology and economy and are still manageable because they are not yet widespread.


    How we manage other weeds:

    On our active restoration projects, we also work to remove common weeds such as English ivy and Armenian blackberry.

    We do this work in partnership with local watershed councils, neighborhood organizations, the City of Portland and partners of the 4-County Cooperative Weed Management Area.

    We also partner with other agencies to educate the public and survey, track, and respond to new high priority animal (insect) invaders in our region, such as the Emerald ash borer.

    EDRR weeds

    Early Detection Rapid Response weeds

    false brome

    False brome

    Brachypodium sylvaticum

    Garlic mustard infestation

    Garlic mustard

    Alliaria petiolata

    Giant hogweed

    Heracleum mantegazzianum

    Japanese Knotweed_by Maja Dumat_tinyurlcomJapanese-Knotweed_cmyk
    orange hawkweed_Gail Hampshire

    Orange hawkweed

    Hieracium aurantiacum

    Pokeweed USDA_Jeff McMillian
    Photo: King County, WA

    Policeman’s helmet

    Impatiens glandulifera

    Photo: USDA

    Purple loosestrife

    Lythrum salicaria

    spurge laurel

    Staff contact

    Michelle Delepine

    Conservationist & Invasive Species Program Coordinator

    Contact me about:

    Invasive species
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