Invasive Plant Policy Review and Regulatory Improvement Project

Invasive plants are a problem that has become more serious in the City of Portland, and in many other Pacific Northwest cities and counties. The proliferation of invasive plants results in environmental and economic impacts. For example, invasive plants can reduce tree health and longevity, create fuel sources for wildfires, and can outcompete and displace native plants that provide food and cover for native wildlife. Removal of invasive plants and replanting with non-invasive plants can be time-consuming and expensive.

The City of Portland has long-recognized invasive plants as a problem. In 1991, the City published the Portland Plant List which contains three lists: a Native Plants list, a Nuisance Plant List and a Prohibited Plant List. Nuisance and prohibited plants were not allowed to be planted in Environmental Overlay Zones and in Greenway Overlay Zones. At that time, the City also established that prohibited plants were not allowed in City-required landscaping anywhere in the City. In July 2005, the City updated that provision to state nuisance plants and prohibited plants are not allowed in City-required landscaping anywhere in the City.

In response to Resolution No. 36360, the Bureau of Environmental Services led a multi-bureau effort to develop a citywide invasive species management strategy. The final document, the Invasive Plant Management Strategy (Strategy), was published in November 2008. The Strategy calls for numerous actions including protecting the best parks habitat; preventing the establishment of new plant invaders; integrating invasive plant management policies into the City’s Comprehensive Plan; and incorporating new invasive plant regulations into existing City codes.

On August 26, 2009, the City Council adopted Resolution No. 36726, the Invasive Species Resolution. This Resolution adopts the November 2008 Invasive Plant Management Strategy to guide work within all bureaus related to invasive plants, from the present until 2020. The Resolution sets forth that the City owned and managed lands are kept free of rank “A” nuisance species, that the spread of rank “B” nuisance species is limited, and that rank “C” nuisance species are removed as funds are available. Actions for each bureau are identified in the Resolution, with additional details in the Strategy.

To implement certain recommendations in the Invasive Plant Management Strategy, the Bureau of Environmental Services is funding the Bureau of Planning and Sustainability (BPS) to lead an evaluation of City policies and rules relating to invasive plants, and to make recommendations for potential updates and improvements. The evaluation is called the Invasive Plant Policy and Regulatory Improvement Project.

The project includes these four components.

Component 1

Update the Portland Plant List (PPL) to include priority ranks and guidance regarding invasive plants. Staff proposes revisions to the PPL to inform City and community invasive species management activities, program development, and priority setting. 

Component 2

Evaluate opportunities to improve invasive plant control through development and non-development situations, including updates to City codes and rules. Staff has evaluated City codes to determine how they could be used more effectively to manage invasive plant species. 

Component 3

Coordinate with the Portland Plan project to help ensure that invasive species are addressed in the Comprehensive Plan update and Portland Plan work plan. 

Component 4

Research the feasibility of establishing a local noxious or invasive weed law. Staff is analyzing the legality and the potential benefits, costs, and impacts of establishing a local noxious weed law.

Recommendations emerging from this work are now entering the legislative process to amend the Zoning Code, other City codes, and the Portland Plant List. Future changes to technical documents, such as the Erosion Control Manual, are recommended but are not part of this legislative process.