Status of Invasive Plants in Michigan

Invasive Plants by Category

• Aquatic - 4 species, 281 records
• Conifer Trees - 3 species, 20 records
• Forbs/Herbs - 270 species, 13671 records
• Grass or Grasslike - 61 species, 2329 records
• Hardwood Trees - 41 species, 1045 records
• Shrub or Subshrub - 43 species, 1357 records
• Vines - 32 species, 836 records

Top Ten Abundant Invasive Plants (by number of reports)

1. purple loosestrife - 812 reports
2. watercress - 260 reports
3. bittersweet nightshade - 244 reports
4. big chickweed - 225 reports
5. redtop - 201 reports
6. spotted knapweed - 197 reports
7. orange hawkweed - 194 reports
8. perennial sowthistle - 190 reports
9. ladysthumb - 178 reports
10. Canada thistle - 177 reports

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

1. orange hawkweed - 79/83 (95%)
2. buckhorn plantain - 79/83 (95%)
3. purple loosestrife - 78/83 (94%)
4. black medic - 78/83 (94%)
5. red sorrel - 78/83 (94%)
6. common ragweed - 77/83 (93%)
7. annual ragweed - 77/83 (93%)
8. reed canarygrass - 77/83 (93%)
9. European cranberrybush - 77/83 (93%)
10. spotted knapweed - 76/83 (92%)

Counties with the most invasive species reported

1. Washtenaw County - 344 species
2. Kalamazoo County - 338 species
3. Berrien County - 318 species
4. Wayne County - 311 species
5. Lenawee County - 297 species
6. Ingham County - 278 species
7. Oakland County - 278 species
8. Kent County - 264 species
9. St. Clair County - 251 species
10. Emmet County - 242 species

Counties with the least invasive species reported

1. Wexford County - 42 species
2. Missaukee County - 57 species
3. Osceola County - 62 species
4. Lake County - 64 species
5. Gladwin County - 67 species
6. Branch County - 78 species
7. Roscommon County - 82 species
8. Sanilac County - 86 species
9. Otsego County - 86 species
10. Tuscola County - 89 species