Control is required in Township 18 N, Range 2 W, Section 10 and on all transportation and utility rights of way, public land and gravel mines.
  Cortaderia seloana, also known as “Pampas grass”, has been a widely planted favorite in the Northwest for many years.  Native to Brazil , Argentina and Chile, established plants are a common sight in neighborhood landscapes, its feathery, distinctive plumes reaching up to 20 feet in height.  Until recent years Pampas grass seemed to be well-behaved in the Northwest, as they were almost exclusively female plants, grown from root divisions for their superior ornamental qualities.  Now there are both male and female plants sold. Seed packets have been found offered for sale at local garden retail outlets. Both Pampas grass and Jubata grass have escaped and infested large areas in some places in the United States, particularly California, smothering native plants and creating serious fire hazards due to the large amount of dead, dry material that is produced by plants every year.

On October 9, 2013 an escaped population of Pampas grass was discovered off West Bay Drive located on private property.With permission from the property owner, photos above were taken at this site. With the use of a Trimble GPS unit we logged 484 escaped plants on this property. Many seedlings as well as first year plants were found. Some young plants had plumes only 3’ high. For more information and control options, please click here.

Why do so many ornamentals ESCAPE?

Many noxious weeds are, in fact, escaped garden plants. Some escaped plants are temporary wanderers outside our care and nurturing, some only occupy niches where nothing else wants to grow. Some, however, become ecological bullies, crowd out native plants, poison livestock, and damage local ecosystems.

Qualities of Common Ornamental Plants

  • Establish rapidly
  • Grow fast
  • Mature quickly
  • Abundant flowers
  • Adapted to environment
  • Free of major insect or disease problems
  • Easy to propagate

Characteristics of Noxious Weeds

  • Establish rapidly
  • Grow fast
  • Mature quickly
  • Prolific seed producers
  • Adapted or adapt quickly to environment
  • No natural predators or diseases to keep populations in check
  • Produce abundant propagules

How you can help


Have you seen any of these plants on a roadside, hillside, by a river or stream? Have you seen them in a ditch or forested area?  Chances are pretty good that they have escaped cultivation.We are currently monitoring for these species.


Arundo Donax Arundo donax, also known as “Giant Reed”, is a tall, erect perennial grass.  It can look a lot like a rather leafy bamboo, and grows to heights of 20-30 feet when established.  It may have green or variegated leaves.  Arundo spreads by underground rhizomes, forming dense stands.  Where it has escaped cultivation (California and much of the southern United States), Arundo has developed large, difficult to control infestations, and is a very serious fire hazard.
Garlic Mustard Garlic Mustard, one of the fastest spreading invaders in woodland habitats of North America. Up to 3 feet tall with triangular to kidney shaped leaves and small white flowers clustered at tops of stems. Roots and new leaves smell like garlic in the spring.
Oregon Public Broadcasting Television Presentation:Invasive Species Rapid Response


Please remember to report plants in locations where they wouldn't have been planted intentionally.
Thank you!

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Washington State Noxious Weed Control Board Monitor List

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