Erect perennial, herb, 0.3-0.6 m high. Fl. yellow, Oct to Dec or Jan to May. Coastal sand.
Beard’s Provinces: South-West Province.
IBRA Regions: Swan Coastal Plain.
IBRA Subregions: Perth.
IMCRA Regions: Leeuwin-Naturaliste.
Local Government Areas (LGAs): Augusta-Margaret River, Bunbury, Perth.
Alternative Names. Berkheya Thistle, Hamelin Thistle, Augusta Thistle.
General Biology. Growth form. Herb. Life form. Perennial. Reproduction. Primarily seed, also stem and root fragments. Dispersal. Adhesion, soil. Seedbank persistence. Medium/long term.
Notes. Has an extended flowering period if sufficient moisture is available. Top growth dies with the onset of early autumn and/or drought. In late autumn new rosettes arise from the old crown or rhizome buds. Not grazed. Unlike other thistles, seeds lack the mechanisms for wind dispersal. Local spread occurs via creeping undergrond stems (rhizomes) and/or layering. Forms a persistent soil seedbank. Large infestations can impede access. Declared weed in Western Australia and Tasmania.
Additional information. Origin. South Africa. History of use/introduction. Ship ballast.
Suggested method of management and control. Dig out and destroy single plants before flowering. As much of the rhizome as possible should also be removed. For larger infestations, try Lontrel® 10 ml/10 L + wetting agent at early rosette stage otherwise use 0.5% glyphosate. Spring application before flowering is usually the most successful. 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.
Legend: Y = Yes, regularly, O = Occasionally, U = Uncertain, referred by others but not confirmed.