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Sonchus oleraceus L.
Common Sowthistle

Sp.Pl. 2:794 (1753)
Conservation Code
Not threatened
Naturalised Status
Alien to Western Australia
Name Status

Erect annual, herb, to 1.5 m high. Fl. yellow, Jan to Dec. Variety of soils. Weed of waste places & disturbed ground.

Amanda Spooner, Descriptive Catalogue, 10 February 2006


IBRA Regions
Avon Wheatbelt, Carnarvon, Central Ranges, Coolgardie, Dampierland, Esperance Plains, Gascoyne, Geraldton Sandplains, Great Victoria Desert, Hampton, Indian Tropical Islands, Jarrah Forest, Little Sandy Desert, Mallee, Murchison, Nullarbor, Ord Victoria Plain, Pilbara, Swan Coastal Plain, Victoria Bonaparte, Warren, Yalgoo.
IBRA Subregions
Ashburton, Cape Range, Carlisle, Carnegie, Central, Chichester, Dandaragan Plateau, Eastern Goldfield, Eastern Mallee, Eastern Murchison, Edel, Fitzgerald, Geraldton Hills, Hamersley, Hampton, Katanning, Keep, Lesueur Sandplain, Mann-Musgrave Block, Mardabilla, Merredin, Northern Jarrah Forest, Nullarbor Plain, Perth, Pindanland, Purnululu, Recherche, Roebourne, Rudall, Shield, Southern Cross, Southern Jarrah Forest, Tallering, Trainor, Warren, Western Mallee, Western Murchison, Wooramel.
IMCRA Regions
Abrolhos Islands, Central West Coast, Eucla, Leeuwin-Naturaliste, Pilbara (offshore), Shark Bay, WA South Coast, Zuytdorp.
Local Government Areas (LGAs)
Albany, Armadale, Ashburton, Augusta Margaret River, Bayswater, Beverley, Boddington, Bridgetown-Greenbushes, Broome, Bruce Rock, Bunbury, Busselton, Cambridge, Capel, Carnamah, Carnarvon, Chapman Valley, Chittering, Christmas Island, Cockburn, Collie, Coolgardie, Coorow, Corrigin, Cuballing, Cue, Dalwallinu, Dandaragan, Dardanup, Denmark, Donnybrook-Balingup, Dundas, East Pilbara, Esperance, Exmouth, Gingin, Gnowangerup, Goomalling, Gosnells, Greater Geraldton, Halls Creek, Harvey, Irwin, Jerramungup, Kalamunda, Kalgoorlie-Boulder, Kent, Kondinin, Koorda, Kulin, Kwinana, Lake Grace, Laverton, Leonora, Mandurah, Manjimup, Meekatharra, Melville, Menzies, Merredin, Mingenew, Moora, Morawa, Mount Magnet, Mount Marshall, Mundaring, Murray, Nannup, Narrogin, Nedlands, Ngaanyatjarraku, Northam, Northampton, Perenjori, Perth, Pingelly, Ravensthorpe, Rockingham, Shark Bay, South Perth, Swan, Trayning, Upper Gascoyne, Victoria Plains, Vincent, Wanneroo, Waroona, West Arthur, Westonia, Williams, Wiluna, Wongan-Ballidu, Woodanilling, Wyalkatchem, Wyndham-East Kimberley, Yalgoo, Yilgarn, York.

Management Notes (for the Swan NRM Region)

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

Notes. May be biennial. A single plant may produce up to 8,000 seeds. Seed is able to germinate all year round over a broad range of temperatures and is favored by light, with emergence highest in seed present on the soil surface. Resistance to herbicides such as chlorsulfuron and atrazine has led to Sowthistles, including Sonchus oleraceus, being the target of biological control programs overseas and in Australia. Preliminary surveys for suitable control agents found two potential organisms: a rust fungus and eriophyid mite. Hybridises with S. asper.

Additional information. Similar exotic species. Sonchus asper. Similar native species. S. hydrophilus.

Suggested method of management and control. Remove small and/or isolated populations manually prior to seed set. Slashing is often ineffective as flowers continue to be produced. Spot spray Lontrel® 10 ml/10 L + wetting agent preferably 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 Y Y Y Y          
Active Growth         Y Y Y Y Y Y Y    
Flowering                 Y Y Y Y  
Fruiting Y                   Y Y  
Manual Removal           Y Y Y Y Y O    
Herbicide Treatment           Y Y Y O        

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



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