Erect annual or biennial, herb, 0.1-0.6(-1) m high. Fl. blue/blue-purple/pink/white, mainly Sep to Dec or Jan. Weed of roadsides, vacant lands & disturbed grounds.
Alternative Names. Salvation Jane, Blueweed, Lady Campbell, Riverina Bluebell.
General Biology. Growth form. Herb. Life form. Annual. Reproduction. Seed. Dispersal. Water, machinery, animals (ingestion and adhesion), contaminated hay and grain. Toxicity. Poisonous to mammals, potential allergen. Seedbank persistence. Up to 6 years. Fire response. Smoke can stimulate seedling emergence.
Notes. Can also be biennial. Widespread weed in warm temperate regions, found mostly in areas dominated by winter rainfall. Adapted to a wide range of soils. Forms dense monocultures. Produces large amounts of seed that can germinate at any time throughout the year, however most germination occurs after substantial rains in autumn and winter. Seed may remain dormant in the soil for up to 6 years but most will germinate within 2 years. Roughened seed coats allow seed to adhere to wool, fur and clothing. Herbicide resistance to Group B/2 herbicides has been recorded in Western Australia. A biological control program started in the late 1980s and 6 agents have since been released. The first, a leaf-mining moth is widely distributed but has had limited impact. Of the remaining six agents, four are currently being redistributed across southern Australia. Declared plant in Western Australia.
Additional information. Origin. Macaronesia, temperate asia. History of use/introduction. Ornamental, bee-plants, seed contaminant.
Suggested method of management and control. Plants are best treated when young. Spot spray in late autumn/winter when most seed has germinated for the year with 0.5 g/10 L chlorsulfuron + wetting agent, this will also help prevent further germination. Glyphosate at 75 ml -100 ml/15 L or metsulfuron methyl 5 g/ 100 L applied at early flowering will control existing plants. Grubbing and cutting are suitable for young plants as long as 20 to 40 mm of taproot is removed. Slashing or mowing can cause out of season flowering and seed production. 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.