Invasive Periwinkle
Invasive Periwinkle

An invasive weed is usually a non-native plant that spreads rapidly, is difficult to remove, and causes environmental or economic damage by taking over an area. Invasive plant species are having significant negative impacts on landowners throughout Marion County and beyond.

These plants are impacting water quality in important watersheds, disturbing ecosystems by displacing native desirable plants and wildlife and negatively affecting timber production and the agricultural industry.

In the US, the cost estimate for the direct and indirect impacts of invasive plants is $143 billion per year, and in Oregon it is estimated that 21 species of noxious weeds cost $125 million a year to control. (The Economics of Invasive Species, 2011, OSU Sea Grant Publication ORESU-G-09-001).

Invasive plant species, or weeds, are making significant negative impacts to landowners throughout Marion County and beyond. Invasive plant species are impacting water quality in important watersheds, disturbing ecosystems by displacing native and other desirable plants and negatively affecting timber production, the agricultural industry and the economy.


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Invasive Scotch Broom
Invasive Scotch Broom

District Assistance Available

Identification Assistance

Have a plant that’s bugging you? Bring a sample (with flowers if possible) into the Marion SWCD office and have staff help you identify it and provide you with information on control techniques if necessary. In addition, the District has herbarium specimens to aid in identifying plants. If you are curious about any plant, contact us to schedule a site visit to your property.

Education and Outreach

The staff at the Marion SWCD can provide technical assistance regarding manual, chemical, biological or mechanical control of invasive plants. You can also view general control guidelines for plants that are on the Marion County Weed List.

Weed Pulls

Occasionally the District partners with local agencies to host weed pull events around the county. Please check the events calendar to see if any are scheduled in your area. The Glenn-Gibson Watershed Council in Salem has recently formed a local “No Ivy League” to combat ivy. Take a look at their website to see if there are any ivy pull events happening around Salem.

Invasive Plant Surveys

For the past 4 years the Marion SWCD has been addressing invasive plant issues throughout Marion County by surveying and mapping problem areas along the County’s waterways. In the past, surveys have been conducted along the Little North Fork of the Santiam River, the entire North Santiam River from Idanha to its confluence with the South Santiam River, the Santiam River from Jefferson to the Willamette River, Zollner Creek, and Bochsler Creek. Reports, results, maps and more information are available.

Invasive Herb Robert
Invasive Herb Robert

Additional Resources

Marion County Weed District

Marion County, through Ordinance 1225, has created an active weed control district, pursuant to ORS 569.360. The county now has the authority to work with private landowners to assist them in controlling noxious weeds on their lands.

 Oregon Garden Smart

An excellent guide featuring native and ornamental plants you can use in your garden to replace plants known to be invasive.

ODA Noxious Weed Control

The Noxious Weed Control Program exists within the Plant Division of the Department of Agriculture (ODA). The program operates to fulfill part of the Department’s mission to protect Oregon’s agricultural industry and natural resources by preventing and limiting the spread and impact of invasive exotic plant species (noxious weeds) which displace and compete with native and desirable domestic plant species.

OSU Small Farms: Weeds, Poisonous Plants and Other Pests

OSU with their extensive amount of resources has provided a place that aggregates all of their weeds, poisonous plants and other pest information into one place.

Weed Mapper

Weed Mapper is a collection of spatial information on the distribution of noxious weeds listed by the Oregon Department of Agriculture (ODA). The Weed Mapper website provides data maps that are viewable at the state or county levels.

Oregon Invasive Species Council

The purpose of the Oregon Invasive Species Council (OISC) shall be to conduct a coordinated and comprehensive effort to keep invasive species out of Oregon and to eliminate, reduce or mitigate the impacts of invasive species already established in Oregon.

Oregon Department of Fish & Wildlife: Invasive Species

The mission of the Oregon Department of Fish and Wildlife (ODF&W) is to protect and enhance Oregon’s fish and wildlife and their habitats for use and enjoyment by present and future generations.

Pacific Northwest Weed Management Handbook

This handbook is designed as a quick and ready reference of weed control practices used in various cropping systems or site/situations in Idaho, Oregon, and Washington.

Forest Service: Pacific Northwest Invasive Species

Established in 1905, the Forest Service is an agency of the U.S. Department of Agriculture. The Forest Service manages public lands in national forests and grasslands. Here you can find a comprehensive list of resources that addresses a variety of invasive species.

Removal of invasive Parrotfeather.
Removal of invasive Parrotfeather