Portland Parks & Recreation (PP&R) cares for about 8,000 acres of natural areas that keep Portland's air and water clean, support wildlife, and provide unique opportunities for people to experience nature locally.

Invasive plants such as non-native blackberry, ivy, and holly can reproduce rapidly and spread quickly. Plants like these take space, nutrients, water, and light from other plants; they degrade ecological diversity and decrease the habitat and scenic value of our shared public spaces. Once these invaders root and spread, it can take years to clean up the habitat, and many more years to re-establish the native plant community. 

Treating for invasive plants helps native species thrive and supports healthy natural areas for wildlife and people. 

The increase in acres treated for invasive weeds comes mainly from a shift in data collection, moving from Ecologist project estimates to field-logged data in Spraymapper, which captures a fuller picture of actual work, including re-treatments. Real growth also played a part, with more certified staff spraying and about $30,000 in added contractor spending. Natural areas work also fluctuates year to year based on conditions and priorities, so some of the change reflects normal variation.

Data shown in the chart is from chemical treatment of invasive plants only.  Tracking the number of acres treated chemically is part of the Oregon Department of Agriculture (ODA)'s required reporting as well as compliance with PP&R's Salmon Safe Certification.

See more detail by viewing the Parks Levy Annual Reports or the webpage for Protect the Best, PP&R's invasive vegetation management program for natural areas.