Common Sowthistle
Common name
Common Sowthistle
Scientific Name
Sonchus oleraceus
Type of plant
Daisies & Thistles (Family Asteraceae)
About this weed
The Common Sowthistle is an annual or short lived perennial. It often has reddish tinges on its leaves and stems and has yellow thistle shaped flowers. It is native to Eurasia and North Africa.
Description
The Sowthistle is an erect annual growing to 1.5 m high. The leaves are generally flaccid and are weakly prickly or have no prickles at all. Yellow flowers are are held high on the stalk in summer. Some plants may be biennial.
Impact on Bushland
If left will spread over bushland and impact on plant communities. 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.
Location
Widely distributed throughout West Australia usually growing in waste places and on disturbed ground.
Priority for removal
Unknown:
Management (hand)
Remove small and/or isolated populations manually prior to seed set. Slashing is often ineffective as flowers continue to be produced. Preliminary surveys for suitable control agents found two potential organisms: a rust fungus and eriophyid mite.
Management (herbicide)
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. Spray herbicide in June, July and August for optimal treatment. 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.
Flowering month/s
All year
Flower colour/s
Yellow
Information source
https://florabase.dpaw.wa.gov.au/browse/profile/8231
Additional information
https://florabase.dpaw.wa.gov.au/weeds/swanweeds/
Hussey, B.M.J., Keighery, G.J., Dodd, J., Lloyd, S.G. and Cousens, R.D. (2007) Western weeds. A guide to the weeds of Western Australia, Second Edition, The Weeds Society of Western Australia, Victoria Park, Western Australia.
