Cotton Fireweed (Senecio quadridentatus)

Cotton Fireweed (Senecio quadridentatus), a native Australian member of the genus demonstrating that its exotic cousins are not the only members of Senecio with capacity to exploit urban soils and disturbance regimes.

An indigenous aster well-adapted to tough conditions, Cotton Fireweed is broadly distributed across Victoria. It can form a short-lived perennial rhizome that reshoots after summer heat, fire or other disturbances, or it can grow as an annual where conditions are tougher. As the name implies, its wind-spread seeds, accumulated in local seed banks over a number of years, can form a major component of early post-fire growing seasons.

The plant is tolerant of a wide variety of compromised growing positions, including urban pavements and structural niches, doing its best to survive the poor urban situations into which its seeds are sometimes deposited.

Unpalatable and toxic to cattle and horses, Cotton Fireweed has proven adept with modern Australia’s super-phosphate regimes. This has meant that it can become an occasional ‘native pest’ of poorly managed land in the state’s interior, where it temporarily dominates newly cleared or fertilised pastures and croplands.

The plant can also establish large, ephemeral monocultures in native woodlands, perhaps as a response to disturbance events, phosphate blooms from neighbouring land uses, or grazing pressures. The effect can be sublime, as seen in the last photograph, taken at Gresswell in December.