Ian Higgins identified this flower as a Gladiolus specie, probably G.undulatus. It is a weed that several FOBIF members found growing in great numbers beside a roadside in Sutton Grange. Unfortunately, as in the case of Gazanias, Gladiolus undulatus, it is still sold in nurseries.
Apart from their effect on bushland, weeds cost Australian agriculture $4 billion a year in decreased productivity and management costs. 65% are escapes from gardens and parks (Ref: www.weeds.gov.au). For more information and discussion about the impact of weeds on our bushlands see the Natural Newstead site.