Report Appendix A Ontario Weed Act – Schedule of Noxious Weeds
Please note, the Act is generally intended to apply only to those areas where these plants may impair agricultural or horticultural operations.
Common Name                           Scientific Name 
1    Barberry, Common                      Berberis vulgaris L.
2    Buckthorn, European                  Rhamnus cathartica L.
3    Carrot, Wild                                 Daucus carota L.
4    Colt’s-foot                                    Tussilago farfara L.
5    Dodder spp.                                 Cuscuta spp.
6    Goat’s beard spp.                        Tragopogon spp.
7    Hemlock, poison                         Conium maculatum L.
8    Johnson Grass                            Sorghum halepense (L.) Persoon
9    Knapweed spp.                           Centaurea spp.
10    Milkweed spp.                           Asclepias spp.    NATIVE
11    Poison-ivy                                  Rhus radicans L.    NATIVE
12    Proso millet, black-seeded        Panicum miliaceum L. (black-seeded biotype)
13    Ragweed spp.                            Ambrosia spp.    NATIVE
14    Rocket, yellow                            Barbarea spp.
15    Sow-thistle, annual, perennial    Sonchus spp.
16    Spurge, Cypress                         Euphorbia cyparissias L.
17    Spurge, leafy                               Euphorbia esula L. (complex)
18    Thistle, bull                                  Cirsium vulgare (Savi) Tenore
19    Thistle, Canada                           Cirsium arvense (L.) Scopoli
20    Thistle, nodding spp.                   Carduus spp.
21    Thistle, Russian                           Salsola pestifer Aven Nelson
22    Thistle, Scotch                              Onopordum acanthium L.
23    Vetchling, tuberous                       Lathyrus tuberosus L.
24    Hogweed, Giant                            Heracleum mantegazzianum