Mexican Fleabane, Seaside Daisy (Erigeron karvinskianus). Infinitely spreading, this is a favoured Melbourne fence and border floss, but also a covert weed that has made the jump to natural areas throughout southern Australia (and to a variety of other contexts around the world).
When a plant ‘loves to grow, flower and thrive almost anywhere’ (contemporary nursery description), this should perhaps raise one’s suspicions. Or as a 1990s recommendation in the Canberra Times put it, ‘Indispensable … once established you will never be without it, for it seeds generously in nooks and crannies … and will thrive in the poorest of soils.’
Promoted in newspaper garden columns from at least the 1880s in South Australia (under an old name, Vittadenia triloba), naturalised botanical collections of Mexican Fleabane were unsurprisingly first made in SA in the early decades of the twentieth century. The plant was soon also recorded in NSW and Tasmania; however despite its ubiquity in Melbourne cottage gardens, the first recorded collections in Victoria date only to the 1960s-1970s.
Frames 1-8: Mexican Fleabane in rocky riparian shoulder conditions on the Merri Creek; 9: as a in Northcote bluestone road gutter; 10: infesting a brick retaining wall in Richmond.