Status of Invasive Plants in Washington

Total number of exotic species reported: 601

Total number of records in EDDMapS: 22651


Invasive Plants by Category

  • Aquatic - 16 species, 1570 records
  • Conifer Trees - 2 species, 2 records
  • Forbs/Herbs - 366 species, 12544 records
  • Grass or Grasslike - 86 species, 3150 records
  • Hardwood Trees - 43 species, 583 records
  • Shrub or Subshrub - 47 species, 1108 records
  • Vines - 30 species, 1006 records

Top Ten Abundant Invasive Plants (by number of reports)

  1. common yarrow - 1626 reports
  2. cheatgrass - 495 reports
  3. Himalaya blackberry - 403 reports
  4. common St. Johnswort - 388 reports
  5. Eurasian water-milfoil - 346 reports
  6. yellow iris - 284 reports
  7. foxglove - 248 reports
  8. bull thistle - 240 reports
  9. Canada thistle - 235 reports
  10. purple loosestrife - 206 reports

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

  1. Canada thistle - 39/39 (100%)
  2. bull thistle - 39/39 (100%)
  3. common yarrow - 39/39 (100%)
  4. field bindweed - 39/39 (100%)
  5. common St. Johnswort - 39/39 (100%)
  6. oxeye daisy - 38/39 (97%)
  7. reed canarygrass - 38/39 (97%)
  8. spotted knapweed - 37/39 (95%)
  9. Japanese knotweed - 37/39 (95%)
  10. diffuse knapweed - 37/39 (95%)

Counties with the most invasive species reported

  1. King County - 465 species
  2. Klickitat County - 362 species
  3. Whitman County - 345 species
  4. San Juan County - 334 species
  5. Okanogan County - 295 species
  6. Pierce County - 280 species
  7. Walla Walla County - 278 species
  8. Whatcom County - 271 species
  9. Spokane County - 270 species
  10. Pend Oreille County - 262 species

Counties with the least invasive species reported

  1. Douglas County - 98 species
  2. Franklin County - 109 species
  3. Garfield County - 128 species
  4. Lincoln County - 135 species
  5. Mason County - 145 species
  6. Adams County - 149 species
  7. Grant County - 162 species
  8. Jefferson County - 168 species
  9. Wahkiakum County - 170 species
  10. Grays Harbor County - 170 species

Report created on April 19, 2014 at 05:27 AM by the UGA Center for Invasive Species and Ecosystem Health using EDDMapS Technology and Data.



Bugwood Center Developed by The University of Georgia - Center for Invasive Species and Ecosystem Health.
Last updated on Tuesday, December 04, 2012 at 08:59 AM