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Sonchus asper (L.) Hill
Rough Sowthistle

Herb.Brit. 1:47,Tab.34,Fig.2 (1769)
Conservation Code
Not threatened
Naturalised Status
Alien to Western Australia
Name Status

Erect, robust, spiny annual or biennial, herb, to 1.8 m high. Fl. yellow, Oct to Dec or Jan. White to grey sand, brown clayey loam, black sandy loam, black clayey peat. Dunes, valleys, seasonally wet areas, watercourses, lakes and wetlands, disturbed sites.

Amanda Spooner, Descriptive Catalogue, 10 December 2007


IBRA Regions
Avon Wheatbelt, Carnarvon, Coolgardie, Esperance Plains, Geraldton Sandplains, Hampton, Jarrah Forest, Mallee, Swan Coastal Plain, Warren.
IBRA Subregions
Cape Range, Dandaragan Plateau, Eastern Mallee, Fitzgerald, Hampton, Katanning, Lesueur Sandplain, Mardabilla, Merredin, Northern Jarrah Forest, Perth, Recherche, Southern Cross, Southern Jarrah Forest, Warren, Western Mallee.
IMCRA Regions
Local Government Areas (LGAs)
Albany, Armadale, Augusta Margaret River, Bayswater, Boyup Brook, Bridgetown-Greenbushes, Busselton, Carnarvon, Chittering, Cockburn, Collie, Cranbrook, Cuballing, Dandaragan, Denmark, Dundas, Esperance, Gingin, Kent, Lake Grace, Manjimup, Mount Marshall, Murray, Nannup, Narembeen, Northam, Plantagenet, Ravensthorpe, Rockingham, Serpentine-Jarrahdale, Swan, Toodyay, Victoria Plains, Wagin, Waroona, West Arthur, Williams, Wyalkatchem, Yilgarn, York.

Management Notes (for the Swan NRM Region)

Alternative Names. Rough Sowthistle, Spiny Sow Thistle.

General Biology. Growth form. Herb. Life form. Annual. Reproduction. Seed. Dispersal. Wind, occasionally water. Seedbank persistence. 1-2 years.

Notes. May be biennial. Most seed germination occurs in autumn or spring but can occur thoughout the year. Seeds are equipped with a small pappas for wind dispersal over large distances. Cut stems exude a milky sap. Sowthistle species including Sonchus asper have been the target of biological control programs overseas. In Australia preliminary surveys for biological control agents found a potential rust fungus and eriophyid mite. Biotypes in Canada have been found to be resistant to metsulfuron methyl. Can hybridise with Sonchus oleraceus.

Additional information. Origin. Europe, tropical and temperate Asia, Africa, however its exact native range is obscure. Similar exotic species. Sonchus oleraceus. Similar native species. S. hydrophilus.

Suggested method of management and control. Slashing is often ineffective as plants can continue producing flowers and seed. Remove small and/or isolated populations manually prior to seed set. Otherwise apply Lontrel® at 10 ml/10 L + wetting agent preferably when plants are at the rosette stage. Read the manufacturers' labels and material safety data sheets before using herbicides. For further information consult the Australian Pesticides and Veterinary Medicines Authority to determine the status of permits for your situation or state.

Management Calendar

Calendar Type Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Comments
Germination O O O O Y Y O O Y Y O O  
Active Growth           Y Y Y Y Y Y    
Flowering                 Y Y Y Y  
Fruiting     O O             Y Y  
Manual Removal           Y Y Y Y Y      
Herbicide Treatment           Y Y O          

Legend: Y = Yes, regularly, O = Occasionally, U = Uncertain, referred by others but not confirmed.



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  • Tamar Valley Weed Strategy (1997) Sow and Prickly Sow Thistles (Sonchus oleraceus and Sonchus asper ssp. glaucescens). Dept. of Primary Industries, Water and the Environment, Tasmania. URL: - Accessed May 2010.
  • USDA, ARS, National Genetic Resources Program (2009) Germplasm Resources Information Network - (GRIN). National Germplasm Resources Laboratory, Beltsville, Maryland. URL: - Accessed October 2009.