With their sprays of golden blossoms and their unique foliage, wattles are arguably the most recognisable plants in Australia. Wattle species can be found in most ecosystems around the country, one of which is our national floral emblem - you may have noticed the golden wattle (Acacia pycnantha) on Australia’s Coat of Arms.
Wattles belong to the genus Acacia, the largest genus of vascular plants in Australia. Australia is home to some 1,350 species of wattle, with around 28 of these occurring naturally in Victoria, including silver wattle (Acacia dealbata), blackwood (Acacia melanoxylon), and prickly moses (Acacia verticillata).
Wattles are diverse in their growth habit, and possess fascinating foliage and flowers. While the vast majority of species form shrubs and small trees, some creep and sprawl across the ground and others can grow to heights of 30 metres.
One of the more interesting features of this genus is their strange foliage. No matter the species, wattle saplings all start out with ‘bipinnate’ leaves. Botanically, this means that their leaves are divided twice: once into pinnae, and then again into pinnules (also known as leaflets). Some species of wattle, such as the silver wattle, retain this leaf form throughout their lives.
Strangely, most species of Acacia transition from this bipinnate leaf form and develop ‘phyllodes’ as they age. Phyllodes are not true leaves, and are actually flattened leaf stalks (petioles). These phyllodes are the narrow leaf-like structures you see on many adult wattles, including blackwood trees. Some species, such as prickly moses, have evolved needle- or spine-like phyllodes, which help minimise water loss by reducing the surface area of the leaf.
Wattle flowers are globular clusters of their stamens, with the flower’s petals barely visible. These flowers act as a food source for many bird species, with their nectar attracting several species of honeyeaters, and seeds attracting cockatoos, rosellas and native pigeons.
Wattles are as iconic as kangaroos, emus and Vegemite. Today, on the first day of spring, notice the beautiful wattles around you and celebrate their beauty and diversity!
Emma Walsh is Secretary for Wild Melbourne and a science graduate who enjoys sharing her love of nature with others. In the past, she has worked as a wildlife presenter, and enjoys teaching children about our native wildlife and its conservation. Her other interests include gardening and bushwalking.
Find her on Twitter at @emmalwalsh91.