Common brassbuttons

Common brassbuttons (Cotula australis) is an annual herb belonging to the Asteraceae family. This weed is characterized by its small, fern-like foliage and tiny, yellow, button-like flower heads. It is a prolific seeder, capable of colonizing large areas in a relatively short time.

The plant is native to Australia but has become naturalized in many regions worldwide. It thrives in diverse environments, including gardens, plant nurseries, cultivated fields, and urban landscapes. It is particularly problematic in areas with moist, disturbed soil and can quickly become an invasive element in turf and ornamental beds.

Biologically, the species is highly adaptable, exhibiting rapid growth rates and the ability to reproduce under varying environmental conditions. It can germinate in cool weather, often preceding many major crops. The plant completes its life cycle quickly, allowing multiple generations to occur within a single season.

The economic impact of Cotula australis stems from its competitive nature. It competes with crop seedlings for moisture and nutrients, potentially reducing yields. Additionally, in nursery settings, it acts as a nuisance weed that increases maintenance costs and can harbor various plant pathogens.

Effective control strategies include:

• Manual weeding or mechanical cultivation before the plant sets seeds.
• Applying organic or synthetic mulches to prevent seed germination in gardens.
• Using post-emergence herbicides registered for broadleaf weed control.
• Maintaining vigorous crop or turf density to outcompete the weed for sunlight and space.