Council's 'problematic' move on Aussie roadside highlights nationwide threat

Yahoo

6 days ago

Australia's network of roads can be plain ugly, so what could be prettier than a local council planting a bed of pretty flowers across the surrounding nature strip? Unfortunately, experts have identified an often overlooked problem created beside one roundabout, just 6km west of Melbourne's CBD, where instead of local native plants, 'highly invasive' gazanias have been planted.
Dr Ali Bajwa's Weed Science Group at La Trobe Institute for Sustainable Agriculture and Food has been investigating the impact of the species on the environment and agriculture, and he believes they are 'problematic'. The plant spiked in popularity in Australia during the 1950s and 1960s, but despite its known problems, it continues to be sold in nurseries and planted by councils.
'They spread quite rapidly. We've seen places where they've covered everything and replaced all of the remnant vegetation. They were introduced as ornamental plants, mainly grown in gardens and nature strips, and we believe that's where they've spread from,' he told Yahoo News Australia.
Gazanias are known for their fierce growth, which ensures the species smothers native groundcovers and wildflowers, leading to a loss of native plant diversity. While its flowers and leaves are pretty to look at, they provide little habitat or food for native animals or insects.
The plant can spread through garden waste, or via seeds or root systems when it's in the ground. Although some modern species have sterile seeds and this helps restrict its impact on the environment.
Gazania is now a common sight along roadsides, particularly in Victoria and South Australia. When the species invades paddocks, farmers struggle to manage its spread, as standard herbicides are generally ineffective.
Bajwa believes the 'horse has already bolted' when it comes to the invasion of gazania, but that doesn't give gardeners an excuse to plant more. The problem is clearly bigger than just one cluster, pictured on the side of the road in Footscray.
'Councils should be thinking of replacing them with more desirable species, like natives, which can grow well under the same conditions,' he said.
Will the roadside gazanias be removed by council?
Some local governments have already pulled them out to try and help the environment, but others are yet to do so. There doesn't appear to be any immediate plans to remove the gazanias or the invasive agapanthus growing in the roundabout in Footscray.
Maribyrnong City Council, which manages the nature strip, did not respond directly to questions from Yahoo News about whether it was aware of the gazanias, why it was allowing them to flourish, or what it planned to do about the problem.
'Council uses a variety of native and non-native species in open space plantings to suit the character of different areas,' its CEO Celia Haddock said in a statement.
'Council does not plant declared noxious weeds and we continue to look for opportunities to prioritise native plants, and improve planting practices where suitable.'
How councils can avoid spreading invasive plants
To avoid the spread of more weeds into Australia's fragile environment, the Invasive Species Council (ISC) advises that local governments should opt for native plants.
Speaking generally about the issue, spokesperson Imogen Ebsworth said there's simply not enough information available as to what has become invasive, or is likely to in the future.
'The result of that is that councils then sometimes find they've inadvertently planted an invasive species that then becomes a problem for them to manage on their own land, and also impacts others,' she told Yahoo.
'A way for councils to address this would be to really focus on plants that are natural to the local area, and are not invasive.'
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The ISC's solution to the problem is to approve national regulations that would prohibit the sale of invasive plants, taking the onus off councils and home gardeners to know what is problematic.
'We've got a situation where over 75 per cent of the invasive weeds we deal with have started their life as garden ornamentals, and a lot of them take 50 years or so for it to become clear that they're really invasive,' Ebsworth said.
'So we've got this huge time lapse gap where we've got over 30,000 introduced plants into Australia, most of them have not been assessed for whether they are weeds or could become weeds. So the information is really imperfect for decision makers. At the local council level, that means good intentions sometimes turn into invasive problems.'
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