Status of Invasive Plants in Wisconsin

Invasive Plants by Category

• Aquatic - 9 species, 1427 records
• Conifer Trees - 2 species, 42 records
• Forbs/Herbs - 232 species, 14603 records
• Grass or Grasslike - 50 species, 3477 records
• Hardwood Trees - 31 species, 926 records
• Shrub or Subshrub - 33 species, 938 records
• Vines - 21 species, 690 records

Top Ten Abundant Invasive Plants (by number of reports)

1. wild parsnip - 2114 reports
2. teasel - 1367 reports
3. common reed - 953 reports
4. Eurasian watermilfoil - 791 reports
5. curlyleaf pondweed - 558 reports
6. spotted knapweed - 537 reports
7. Japanese knotweed - 288 reports
8. purple loosestrife - 218 reports
9. redtop - 204 reports
10. big chickweed - 194 reports

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

1. purple loosestrife - 73/72 (101%)
2. yellow toadflax - 72/72 (100%)
3. European cranberrybush - 72/72 (100%)
4. white campion - 72/72 (100%)
5. bladder campion - 71/72 (99%)
6. common mullein - 70/72 (97%)
7. hoary alyssum - 70/72 (97%)
8. red clover - 70/72 (97%)
9. Eurasian watermilfoil - 69/72 (96%)
10. bull thistle - 69/72 (96%)

Counties with the most invasive species reported

1. Dane County - 315 species
2. Milwaukee County - 275 species
3. Walworth County - 266 species
4. Sheboygan County - 255 species
5. Rock County - 249 species
6. Brown County - 242 species
7. Racine County - 240 species
8. Kenosha County - 230 species
9. Waukesha County - 220 species
10. Richland County - 212 species

Counties with the least invasive species reported

1. Menominee County - 66 species
2. Burnett County - 88 species
3. Pepin County - 88 species
4. Clark County - 89 species
5. Rusk County - 96 species
6. Barron County - 97 species
7. Florence County - 101 species
8. Eau Claire County - 102 species
9. Washburn County - 106 species
10. Iron County - 108 species