Gazania is no longer just a roadside problem—this resilient invader is making its way into cropping paddocks, posing significant challenges for farmers across the Southern region. Thanks to research funded by GRDC and led by Dr. Ali Bajwa, Senior Lecturer in Weed Science at La Trobe University, growers now have hope for practical solutions. Here are the top five things you need to know about Gazanias and the ongoing fight against their spread.
✅ 1. Gazanias Are Built for Survival
Gazanias are incredibly hardy and prolific seed producers. Originally from South Africa, they have adapted well to Australia’s inland conditions, making them drought-tolerant and difficult to control. Their thick, waxy leaves hinder herbicide absorption, and their ability to reproduce through both seeds and underground rhizomes ensures their persistence.
Large number of seeds deposited under a single gazania plant (Photo: Ali Bajwa).
✅ 2. Gazanias Thrive in Tough Conditions
Drought seasons provide an advantage for Gazanias. Their ability to shut down growth and conserve resources allows them to survive harsh conditions, ready to bounce back when the season turns favourable. Farmers need to be vigilant during these times, as dry conditions reduce chemical effectiveness.
✅ 3. Early Results Show Promise
The project includes glasshouse experiments at La Trobe and field trials in Loxton and Arno Bay, comparing chemical control options for inland and coastal populations. A wide range of chemistries is being evaluated for burndown/post-emergent control at this stage.
Early results show that high rates of glyphosate in combination with Group 14 herbicides such as Sharpen (active ingredient: saflufenacil) or Voraxor (active ingredients: saflufenacil + trifludimoxazin) provide complete (100%) control of gazania plants with up to 12 leaves under glasshouse conditions. These treatments have also provided effective (>90%) control so far under field conditions in Loxton. The use of right adjuvants is also critical in improving herbicide uptake and efficacy against a tough weed like gazania. For example, 1% Hasten did the trick for these treatments.
Gazania control trial in Loxton (Photo: Ali Bajwa).
✅ 4. Timing Is Everything
Dr. Bajwa’s research highlights that timing is critical for effective management. Herbicide efficacy drops by up to 50% once the plant exceeds the 10-12 leaf stage. Early intervention, targeting young plants (2-4 leaf stage), is the best approach to keep these weeds under control.
✅ 5. Managing Gazanias Requires a Multi-Pronged Approach
There’s no silver bullet for Gazania control. Alongside chemical options, mechanical removal and vigilant monitoring are essential. Farmers with optical sprayers where higher rates of herbicide can be applied to spot spray Gazanias are more likely to be able to achieve efficient control, especially in summer months when this species tend to thrive. However, further R&D is required to develop integrated weed management (IWM) strategies for gazania.
This work is part of the GRDC NGN project, focusing on Gazania incidence and its impact on grain cropping in the Southern region (GRDC Code: ULA2402-002RTX).
A big thanks to the farmers and industry professionals that have been instrumental in providing valuable insights and feedback.
👉 What’s Next?
Stay tuned for updates as field trials continue and results start to roll in. For more information, follow Dr. Ali Bajwa on Twitter/X (@a1bajwa) or check the GRDC updates. The project team is continuing farm surveys, so if you are having troubles managing gazanias in grain production systems, please get in touch with Dr. Bajwa. With collective effort, we can turn the tide in the ‘Gazania Wars’ and help farmers regain control of their paddocks.
Dr Ali Bajwa can be contacted at A.Bajwa@latrobe.edu.au or 0431 194 862.
