Blackberry bushes are located along many of the City of Hobart's waterways, and can be seen in full bloom during summer and autumn, when the blackberries are in full fruit and ripe for the harvesting. However, despite their benefits to people and wildlife, blackberry is a significant environmental and agricultural weed in Tasmania.
Blackberries, Rubus fruticosus, survive and spread very successfully in open environments such as disturbed bush, on the banks of waterways, along roads, tracks and fences and within agricultural landscapes. Once established, blackberries are incredibly difficult to remove. They form dense thickets covered in thistles, and their root system are deep and extensive.
Once blackberry has established in an area, it can outcompete and prevent the growth of native vegetation. While it provides shelter and food for native wildlife, such as the vulnerable Eastern Barred Bandicoot, it provides similar resources for invasive species, often increasing their populations where present.
Because of these reasons, blackberry is a declared weed under the Tasmanian Weed Management Act, 1999 as well as a Weed of National Significance.
Treating blackberry can be particularly challenging due to its prickly nature, potential habitat and food for rare wildlife, and ability to stabilise waterway banks.
Herbicides are the most effective control for this species, and often works well in combination with other methods. Specific herbicides can be sprayed over the leaves, or if the majority is cut back, can be painted on the remaining roots and stems. Goats are also effective at starting to control large infestations!
If blackberry is growing along slopes, or native wildlife is known to be present, a staged approach is often best- gradually remove the weeds and revegetate with native species at the same time.
Important note: Herbicide cannot be used on blackberries while they are in fruit, due to its impact on humans and wildlife.