Early Detection-Rapid Response (EDRR) Weeds

This informative video gives step by step instructions on how to manually remove knotweed from your property.

Early Detection-Rapid Response, or EDRR, promotes prevention methods such as cleaning your boots and bike tires to checking the spread of a new garden plant. If prevention isn’t possible, the most time and cost-effective way to manage new invasive plants is through EDRR efforts. They include early detection while weed populations are small and rapid control measures, increasing the likelihood that new invasions will not become established.

This program is a county-wide partnership that includes East Multnomah Soil and Water Conservation District and the City of Portland Bureau of Environmental Services (BES).

Take a look at our EDRR Final Report 2017-2018.

Please see our current EDRR Target Species List.

The District continues to expand private landowner outreach to survey and control high priority weed species, or EDRR, before they become established. This year we increased our total survey area to nearly 1,500 acres! Our largest program areas continue to be garlic mustard, knotweed and spurge laurel, however several additional important target species were also detected and controlled in smaller numbers.

Invasive garlic mustard

Invasive garlic mustard

Garlic mustard season brought both major gains and challenges. Numerous sites had no or very few new plants. Overall, infestation density continues to drop, however a few previously unknown sites were found (and controlled) that were extremely dense. One of the most significant of these sites was discovered by a couple of weed watcher extraordinaires!

With assistance from Oregon Department of Agriculture, aquatic invasive plant surveys were conducted around the southern portion of Sauvie Island and the Linnton Harbor. Several Phragmites australis (Common Reed) sites received first-time treatment. Also, it’s important to note the aquatic invasive, ludwigia, was discovered (and controlled) at a single site in the Multnomah Channel.

For two years in a row, no new orange hawkweed or pokeweed plants were found at two District-managed sites in SW Portland, however a single new discovery of each of these species were found at other sites. In the Riverview area, a large policeman’s helmet population was found and controlled. Elsewhere in the neighborhood one of three managed giant hogweed sites did not have any new infestations!

In partnership with several other agencies, the District led three weed watcher workshops in Southwest Portland, the Skyline area and Scappoose. In total, 27 volunteers were trained on how to identify and report high priority invasive plant species.

We thank Oregon Department of Agriculture and Oregon Watershed Enhancement Board for their continued support of our garlic mustard program via their award of an Oregon State Weed Board grant.

For more information on the EDRR weeds we focus on, click on the appropriate species:

Invasive spurge laurel

Invasive spurge laurel

False brome

Garlic mustard

Giant hogweed

Japanese knotweed

Orange hawkweed

American pokeweed

Spurge laurel

If you have more questions, contact Michelle Delepine, Invasive Species Coordinator, at or 503.238.4775, ext. 115.


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