Landcare Agony Aunt: some seasonal advice for your landcaring questions
Dear Agony Aunt,
I was dismayed to see Blackberry clumps resprouting on my landcare site yet again this summer. We have tried everything, what can we do?
Blackberry – Caption: Red and blue-black blackberry fruit, and serrated green leaves, Photographer: John Hosking NSW DPI © State of New South Wales
Image licensed under Creative Commons Attribution 4.0 licence
Wild Raspberry – Rubus sp. ROSACEAE
©The Royal Botanic Gardens & Domain Trust
Dear reader,
Good timing! Now is the optimal time to target the weed Blackberry (Rubus fruticosus) before fruit-set. Yes, the fruits are delicious and perfect for making blackberry jam, but it is one of our worst weeds. As you would know, Blackberry spreads easily both vegetatively and by foxes and birds spreading the seeds, quickly growing into large thickets which can take over pasture and native bushland areas. Blackberry is a weed of National Significance and a Regional Priority. If you are unsure which blackberry you have got, as a rule of thumb, the European Blackberry generally has blacker berries, darker leaves, more reddish stems and bigger prickles than Australian native raspberries. Here is an identification key to help.
It is important to check your site at least once per year, and map existing Blackberry clumps and new plants you spot. Dig up small plants with a mattock as soon as you can. The first year canes don’t flower but in the second year reproductive canes develop. These flower in spring and fruit from February to March. If you don’t intervene, each fruit can contain up to 30 seeds and further growth can turn the bushes into 2-3m tall impenetrable thickets. Burning can knock the bushes back but can also stimulate seed germination.
There are a number of effective control methods listed here. For long-term success, it is important to use a combination of methods that suit your site, situation and resources. Your Local Landcare Coordinator can help you plan this. You need to be prepared to monitor and follow-up for several years. In autumn the cane tips can take root creating new plants. Slashing can help reduce plant bulk but there are underground crowns which can regrow and produce lateral suckers, so keep monitoring the clumps and use a follow-up treatment. Grazing with horses after slashing has been used successfully at Wollombi. The plants will be dormant over winter, so if you are considering using herbicide, wait until spring/summer when the plants are actively growing.
If you love eating Blackberries, why not plant the equally delicious Australian native Wild Raspberry? If planting near bushland one of the 4 local Rubus species would be preferred: R. moluccanus var. trilobus (previously R.hillii), R. rosifolius, R. nebulosus or R. parvifolius which has the smallest but tastiest fruits. Wild Raspberry is a great bush tucker plant with a similar habit but much easier to contain and nurture. You can also source thornless varieties for a garden setting. It should be noted that European Blackberry must not be sold anywhere in NSW. Good luck and let us know how you get on with tackling your Blackberries! Don’t give up hope!
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