Hidden gem: Australia’s purple wattle
OF THE THOUSAND species of wattle that call Australia home, purple-flowered wattle (Acacia purpureapetala) has to be the most striking. Decorated in mauve-pink puffs of flower, it can only be found in small patches across north-east Queensland.
According to CSIRO botanist Andrew Ford, its not just the flower’s colour that’s unique. “Purple wattle has an unusual growth form for a wattle. It is dominantly a multi-stemmed sprawling shrub to 50cm high, with several stems arising from a central point near the ground. The stems radiate away from the centre, like the spokes of a bicycle wheel. These stems can be more than one metre long,” he tells Australian Geographic.
Unlike other species of wattle – sometimes considered a pest when it extends its ranges– it’s rare and difficult to cultivate, posing a challenge for conservationists determined to save the species from extinction. “Purple wattle is not easy to cultivate due to the very low number of seeds that form in the pods,” Andrew explains. “This is despite many flowering heads being present on each plant.”
See more: An illustrated guide to Australia’s wattle
An illustration of purple-flowered wattle by Australian geographic botanical illustrator Heidi Willis.
Andrew has been studying purple wattle “seriously and strategically” for just a year, but says he’s had an interest in the species for more than 10 years. He’s worked closely with Bush Heritage Australia, Vegetation Management Science and the National Herbarium of New South Wales to better understand the plant in a new project launched in September last year.
“The main aim was to get a more accurate estimate of the total number of purple wattle plants and to document its distribution by searching for new and unaccounted populations,” he says.
The team established a strategic monitoring team program that recorded threats, disturbances and the last identifiable fire at different population sites.
They made a huge breakthrough early last month when they discovered a new population of the critically endangered plant on the high, rocky slopes of mountains in far North Queensland. Before this new discovery, there was thought to be only an estimated 500 left in the wild –now, they think there might be thousands.
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Since purple wattle was first described back in 1905 by Queensland Government botanist Frederick Marshman Bailey, it’s been considered rare. “Being naturally rare is not uncommon for a plant species,” Andrew says.
“Purple wattle is considered rare due to its relative restricted geographical occurrence and the total low number of mature individuals, which at the time was estimated to number only 500,” he adds.
However, despite being “naturally rare” its numbers have also been significantly depleted following European occupation. According to the Department of the Environment and Energy, grazing activity by cattle, mining, roadworks and infrastructure are primary threats.
Purple wattle isn’t, however, the only wattle with a distinctive flower or stem. There’s also scarlet blaze (Acacia leprosa), sometimes known as the ‘weeping red’ wattle, discovered in 1995 in north-eastern Melbourne and Acacia rubida, found across the Great Dividing Range, which has a unique red stem.
Scarlet blaze. (Image Credit: Wikimedia)
