Early Detection-Rapid Response (EDRR) Weeds

Highly invasive priority weeds are targeted for Early Detection and Rapid Response (EDRR) activities to help prevent them from getting established. Early detection is critical while weed populations are still small, followed by rapid control measures. EDRR activities include methods to prevent the spread of seeds, such as cleaning your boots and bike tires or checking the spread of a new garden plant. If prevention isn’t possible, the most efficient and cost-effective way to manage new invasive plants is through various weed treatments.  Together, these efforts will help prevent these species from becoming established. This program is a county-wide partnership with East Multnomah Soil and Water Conservation District and the City of Portland Bureau of Environmental Services (BES). Please see our current EDRR Target Species List.

Find more information on priority EDRR weeds:

Invasive spurge laurel

Invasive spurge laurel

False brome

Garlic mustard  (Fact Sheet – English, Español)

Giant hogweed (Fact Sheet – English, Español)

Japanese knotweed

Orange hawkweed

American pokeweed (Fact Sheet – English, Español)

Spurge laurel (Fact Sheet – English, Español)

Learn more: Invasive Plants — Identify and root them out!

Progress report – Fiscal Year 2017-2018

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

The District continues to outreach to private landowners to survey and control high priority weed species, or EDRR, before they become established. In 2017-2018, we increased our total survey area to nearly 1,500 acres! Garlic mustard, knotweed and spurge laurel were the three priority species, however we detected and controlled smaller numbers of several additional important target species.

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.

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


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