Thanks to Hilary Bain for her concern about environmental weeds that threaten our biodiversity. Bitou Bush can well be dealt with by trained and supervised hand-weeders, and congratulations to those who make it work.
Some of us accept that herbicide use is unavoidable, since Bitou Bush has now infested about 80 per cent (or more than 900km) of the NSW coastline, extending 10km inland in some areas. It has become the dominant species along about 36 per cent of the state’s coastline (from environment.nsw.gov.au website).
Regardless of acceptance, or not, of the need for low levels of herbicide use, there are obvious ways to minimise future needs for herbicides and protect our biodiversity. It is probably a bit late for Bitou Bush and Camphor Laurel, but there are many environmental weeds in the early stages of expansion, and more are being introduced as we read.
If we take a long-term view and a strategic-management approach that results in containment and ideally at least local eradication of emerging weeds, future herbicide use will be vastly reduced or perhaps unnecessary for these species. Even better, plants with invasive tendencies should not be introduced in the first place (and ‘green, ethical’ businesses, including some nurseries, are still selling these plants).
To give but a few examples of weeds that need serious management now:
Kahili Ginger Hedychium gardnerianum is well established locally and expanding from gardens into bushland by way of bird-dispersed seeds and dumped garden waste. In New Zealand, this species takes over whole hillsides which then have to be aerially sprayed.
Cherry Guava Psidium cattleianum forms dense monocultural stands that displace native forests throughout the Pacific, including Hawai’i and Lord Howe Island. The trees are hard to control even with the more toxic herbicides. Bad infestations are known at Broken Head and Wilsons Creek, with scattered plants everywhere. Those who really want to retain them need to net trees so birds cannot disperse the seeds.
Giant Devil’s Fig Solanum chrysotrichum is a monstrous thorny plant spreading rapidly south from Queensland. Viewing whole paddocks of infestation on the border, it is hard to imagine how control might be possible with any sort of spraying. Herbicide bombs perhaps?
Herbicide use is one aspect of more complex issues. We all need to work together to head off big problems before they become bigger and look around for the gingers, guavas, devil’s figs and the rest of the long list.
Web searches will provide information, photos and many more examples. Also contact local landcare groups and see Council’s website (includes herbicide and non-herbicide control measures).
Wilsons Creek and Annette McKinley, Broken Head