Field Guide     Weed Management     Sow Thistle

Sow Thistle (Sonchus oleraceus L.)

Crop Impacts: Field Crops

Sow Thistle 1

About Annual sow-thistle:

Annual sow-thistle reproduces via seed. The stem can grow to be on average up to 4 feet tall. This weed tends to appear in areas where the soil is moist and this weed thrives in areas where cultivation has occurred. This weed has a history of hosting different viruses and pests such as aphids. Annual sow-thistle has 2 types of leaves, some round with a few spikes/teeth around the edges, and some more arrow shaped with teeth all around, both a green colour, and can appear to have purple veins.

Family: Composite or Aster Family (Compositae)

Sow Thistle 2 Sow Thistle 3

Annual sow-thistle Scouting and Prevention:

Regularly scouting your field for weeds is an effective way to know what weeds are working their way into your crops and fields. Taking random row counts and then changing up which areas you’re checking on a regular basis can be a main factor in whether or not weeds are noticed early enough. Ensure to check different areas, and pay close attention to the outskirts of the fields.

Annual sow-thistle Control:

Tilling on a regular basis or cultivating fields can help reduce reproduction of this weed. Once cultivation occurs, the weed germinates, the more you cultivate your fields, the fewer seeds the weed will be able to produce. Pre and post season herbicide application is essential to preventing this weed from appearing in fields.

Latin / Alternative Annual sow-thistle Names:

  • - Sonchus oleraceus L
  • - Laiteron potager
  • - Common annual sow-thistle
  • - Laiteron lisse
  • - Laiteron commun

Additional Annual sow Thistle Resources:

http://www.omafra.gov.on.ca/english/crops/facts/ontweeds/annual_sowthistle.htm Ontario Government Ag

http://www.weedwreckingcrew.com/ Dupont Weed Wrecking Crew

http://www.precisionpac.com/ Dupont Precision Pac

http://www.umanitoba.ca/afs/plant_science/weeds/fab41s00.html University of Manitoba Ag