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Status of Invasive Plants in Oregon

Total number of exotic species reported: 607

Total number of records in EDDMapS: 242892


Invasive Plants by Category

  • Aquatic - 14 species, 5772 records
  • Conifer Trees - 1 species, 1 records
  • Forbs/Herbs - 379 species, 165151 records
  • Grass or Grasslike - 110 species, 14728 records
  • Hardwood Trees - 33 species, 925 records
  • Shrub or Subshrub - 39 species, 41211 records
  • Vines - 29 species, 4493 records

Top Ten Abundant Invasive Plants (by number of reports)

  1. Canada thistle - 23546 reports
  2. Scotch broom - 22160 reports
  3. common St. Johnswort - 18208 reports
  4. bull thistle - 16532 reports
  5. Himalayan blackberry - 16048 reports
  6. tansy ragwort - 14241 reports
  7. yellow starthistle - 11603 reports
  8. Japanese knotweed - 9047 reports
  9. rush skeletonweed - 8447 reports
  10. diffuse knapweed - 6848 reports

Top Ten Widespread Invasive Plants (by number of positive counties)

  1. Canada thistle - 36/36 (100%)
  2. bull thistle - 36/36 (100%)
  3. redstem filaree - 36/36 (100%)
  4. common yarrow - 35/36 (97%)
  5. common St. Johnswort - 35/36 (97%)
  6. orchardgrass - 35/36 (97%)
  7. soft brome - 35/36 (97%)
  8. soft brome - 35/36 (97%)
  9. curly dock - 35/36 (97%)
  10. curly dock - 35/36 (97%)

Counties with the most invasive species reported

  1. Lake County - 431 species
  2. Multnomah County - 411 species
  3. Lane County - 391 species
  4. Marion County - 369 species
  5. Jackson County - 369 species
  6. Benton County - 357 species
  7. Douglas County - 343 species
  8. Curry County - 300 species
  9. Umatilla County - 277 species
  10. Josephine County - 275 species

Counties with the least invasive species reported

  1. Gilliam County - 117 species
  2. Columbia County - 148 species
  3. Wheeler County - 153 species
  4. Sherman County - 162 species
  5. Deschutes County - 174 species
  6. Tillamook County - 174 species
  7. Crook County - 177 species
  8. Baker County - 185 species
  9. Morrow County - 187 species
  10. Grant County - 192 species

Report created on July 22, 2014 at 05:20 PM by the UGA Center for Invasive Species and Ecosystem Health using EDDMapS Technology and Data.