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The Yamhill Soil and Water Conservation District is the designated weed control agent for Yamhill County. As such, it is the district’s duty to inform landowners about noxious weeds and their control. The term weed is a subjective word used to describe any plant considered that is "out of place." In other words, weeds can include native and non-native plants alike, growing wherever someone wishes they weren't.

No matter where one lives, whether it is town or in the country, invasive weeds are an unfortunate part of our life. In addition to causing trouble in our gardens and fields, they negatively impact the natural ecology of a region.

Link: Weed Control Recommendations

Download: Noxious Weed List 2008-2009
Canada Thistle
English Ivy
Field Bindweed
Himalayan Blackberry
Italian Thistle
Japanese Knotweed
Meadow Knapweed
Puncture Vine
Purple Loosestrife
Reed Canary Grass
Scotch Broom
Tansy Ragwort

Some of the problems weeds may cause -- especially if they are non-natives -- are:

  • reduction of biodiversity
  • loss of and encroachment upon endangered and threatened species and their habitat
  • loss of habitat for native insects, birds, and other wildlife
  • loss of food sources for wildlife
  • changes to natural ecological processes such as plant community succession
  • alterations to the frequency and intensity of natural fires
  • disruption of native plant-animal associations such as pollination, seed dispersal and host-plant relationships


Plenty can be done to control weeds. According to the Plant Conservation Alliance, you can:

  • Avoid disturbance to natural areas, including clearing of native vegetation, planting of non-native plants and dumping of yard wastes.
  • Do not purchase or use invasive exotic species in your landscaping, for land restoration, or erosion control projects.
  • For landscaping, use plants that are native to your local region as much as possible.
  • Know your plants. If you are unsure of the identification of a plant, take a sample to the Yamhill SWCD or the OSU Extension office.
  • Control exotic invasive plants in your landscape either by removing them entirely or by managing them to prevent their spread outside your property. This may include pruning to prevent flowering and seed dispersal or cutting, mowing or herbicide use to prevent vegetative spread.
  • Discuss your concerns about invasive exotic plants with nurseries and garden
    shops and ask them not to sell these species.
  • Notify the Yamhill SWCD of invasive exotic plant occurrences.
  • Offer to assist in exotic plant removal projects.
  • Work with your local government to encourage the use of native plants in their urban and suburban landscapes. Provide them with lists of attractive, non-invasive locally native alternatives that are naturally more hardy, pest-resistant, and provide more nutritious food for wildlife than cultivated plants.