Ontario Weeds: Smooth perennial sow-thistle

Return to the Ontario Weeds Gallery

Excerpt from Publication 505, Ontario Weeds, Order this publication

Table of Contents

  1. Name
  2. Other Names
  3. Family
  4. General Description
  5. Habitat
  6. Similar Species
  7. Related Links

Name: Smooth perennial sow-thistle, Sonchus arvensis L. var. glabrescens Guenth, Grab. & Wimm.,

Other Names: laiteron des champs glabre, Creeping sow-thistle, Field sow-thistle, Perennial sow-thistle, Sonchus uliginosus Bieb

Family: Composite or Aster Family (Compositae

General Description: In Smooth perennial sow-thistle the stems and involucral bracts around the flower heads are smooth, completely lacking the dark glandular hairs characteristic of Perennial sow-thistle.

Photos and Pictures

Smooth perennial sow-thistle.


Habitat: Smooth perennial sow-thistle occupies similar habitats to those of its sister variety. It is common only in extreme southwestern Ontario and in the northern and northwestern parts of the province, although it occurs sporadically elsewhere.

Similar Species: Virtually identical to Perennial sow-thistle in seedling and juvenile stages, being distinguishable only after the flower heads begin to form and open.

Related Links

... on general Weed topics
... on weed identification, order OMAFRA Publication 505: Ontario Weeds
... on weed control, order OMAFRA Publication 75: Guide To Weed Control

| Back to the Ontario Weeds Gallery |


For more information:
Toll Free: 1-877-424-1300
E-mail: ag.info.omafra@ontario.ca
Author: OMAFRA Staff
Creation Date: 01 June 2000
Last Reviewed: 01 November 2003