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The City of Portland, Oregon

Environmental Services

working for clean rivers

Phone: 503-823-7740

Fax: 503-823-6995

1120 SW 5th Ave, Suite 613, Portland, OR 97204

More Contact Info

Your Role in Invasive Plant Control

butterfly bushIf you don't know it, don't grow it. Avoid buying or growing plants such as purple loosestrife, English ivy, ribbongrass, and butterfly bush that are known to be invasive.

Be especially careful when buying plants and seeds on the internet or by mail order. You may unknowingly contribute to the spread of an invasive species from one part of the country to another. Although some companies have voluntarily withdrawn known invasives from sale or labeled these species high risk, many have not.

Find out about invasive plants from our invasive plants poster. You also can get lists of known invaders from state and federal agencies as well as non-profit groups such as The Nature Conservancy, Native Plant Societies, and Oregon Department of Agriculture (see the links below).

ribbongrassTips For Stopping the Spread of Invasive Plants

  • If you see your local nursery selling invasive plants or seeds, let them know about your concerns. Most are interested in avoiding problem species and will listen.
  • Avoid buying and planting mixtures of seeds, especially ones labeled "wildflowers." Many contain invasive species. Others are too poorly labeled to tell.
  • Landscape and garden with plants native to your area. Although many non-native plants are not invasive and can be grown without risk, emphasizing natives (especially pollinator-friendly species) can provide other advantages such as food, cover, or nesting sites for butterflies and birds. Native plants also require less water, fertilizers and pesticides.
  • Don't dump your aquatic plants or aquarium water into local waters. Many plants for water gardens and aquaria are highly invasive. Eurasian watermilfoil, a notorious aquatic weed that spreads rapidly and replaces natives, is one example of a plant that became established after being discarded from a personal aquarium.
  • Be a good neighbor. Never dispose of unwanted plants or lawn or garden clippings in a nearby park or natural area. Invasive plants can spread from plant fragments, seeds, and berries.
  • Share your knowledge about the harm that invasives cause with your family, friends, coworkers and neighbors.
  • Join a local invasive plant eradication effort.
  • Learn to recognize common invaders and keep an eye out for signs of new ones. Check trees, gardens, vacant lots, roadsides, yards, agricultural areas, wetlands, ponds, and lakes. If you think you've found a new infestation, report it to your local soil and water conservation district or to Early detection is crucial to stopping an invasive from becoming permanently established.

These tips are modified from the Union of Concerned Scientists web site at  

Invasive Plant Information on the Web

For gardeners

Information from the National Arboretum

What every gardener needs to know (blog)

Invasive Plant Lists by State

Oregon Department of Agriculture Noxious Weed Profiles

Native Plant Society, Emerald Chapter

Weeds Gone Wild

Information about Invasive Plant Control Methods

Take a Naturescaping workshop. Call 503-222-7645 or visit

Three River Land Conservancy – Backyard Habitat Certification
Gaylen Beatty 503-699-9825

Volunteer Opportunities

Join or volunteer with a local watershed project.

Portland Parks & Recreation

West Willamette Restoration Partnership
Volunteer Coordinator, Amanda Wilson, 503-699-9825

Portland Audubon Society – contact Deanna Sawtelle or 503-292-6855 ext. 108.


Multnomah Weed Watcher Training