The Portland Plant List provides a user-friendly guide to plant species found in Portland and the metropolitan region.
The Portland Plant List is comprised of two lists and supporting information: the Native Plants List and the Nuisance Plants List. Both plant lists are integral to the City of Portland’s natural resource protection programs and invasive species management strategy.
- The Native Plants List provide information about associated habitats, flowering seasons, and whether some of these plants pose additional wildfire risk. Only plants from the Native Plants List may be planted in Environmental Overlay Zones and Pleasant Valley Natural Resource Overlay Zone resource areas. Native plants may be required in the Greenway Overlay Zones as well, and are encouraged throughout the city.
- The Nuisance Plants List identifies species that threaten the health and vitality of native plant and animal communities, humans, and the economy. Nuisance plants are ranked to indicate how invasive or widespread the plant is in Portland. Plants on the Nuisance Plant List may not be planted in any of the overlay zones identified above or in any City-required landscaped areas or mitigation sites.
- The Portland Plant List also includes a Required Eradication List of plants that must be removed if discovered anywhere in the city. These plants are not commonly found in Portland at this time, and must be eradicated if discovered to keep them from spreading.
The Portland Plant List was first established in 1991, with a number of updates since. Key updates over that time include the addition of the prohibited plants list in 1994, substantial restructuring of the document in 1997, and a sizeable increase in the number of nuisance and native plants in 2004. In 2005, incorporation of nuisance plants in City-required landscaping was prohibited.
Information included in the Portland Plant List was further expanded in 2010, with the addition of background information on plant species and the application of rankings for each plant on the Nuisance Plants List. At that time, the Portland Plant List was changed from an ordinance to an administrative rule, providing a more streamlined process for reviewing and updating it. In addition, the Nuisance Plants List and the Prohibited Plant List were consolidated to provide greater clarity.
In 2011 several species were added to the Native Plants List and an area-specific plant list was developed for the Portland International Airport, to ensure consistency with the adopted Airport Futures Project. A plant index for both Native and Nuisance Species was incorporated into the document, as well as information about native tree growth rates in accordance with the adopted Citywide Tree Project.
The most recent update of the Portland Plant List was completed in June 2016. As a part of that update 16 species were removed from the Native Plants List, eight species were added to the Nuisance Plants List and the ranks of three species were reassessed on it, and a number of “housekeeping” items (incl. updates to plant nomenclature, grammatical corrections, etc.) were addressed.
Additionally, the 2016 update included a directive to move the South Waterfront Greenway Native Plant List and Nuisance Plant List to the Portland Plant List Area-Specific Plant Lists upon City Council’s deletion of the South Waterfront plant lists from Title 33, Portland Zoning Code (see 33.510.253, Greenway Overlay Zone in South Waterfront Subdistrict, Subsection E.5.f, Landscaping), expected as a part of the Central City 2035 Plan adoption in early 2017.
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