Wattles belong to the genus Acacia, in the Mimosa family.
There are over 600 different species distributed throughout Australia with shapes varying from low, spreading shrubs to large, upright trees. It is often called 'Mulga'. Whilst most are early spring and summer-flowering, there are wattles that bloom all year round.
Wattles are the most widespread of all Australian plants, some inhabiting the most remote and inhospitable areas, growing in parched sand in the desert under the scorching sun, spiked, hard and leafless. In the rainforest gullies they have soft feathery foliage with pale golden heads.
One species of wattle, Acacia pycnantha, is the floral emblem of Australia and is featured on the coat-of-arms.
Wattle seeds are carried in pods which twist and snap open when crisp and dry, scattering shiny, black seeds; the pods then remain on the plant. The pods are decorative, coiled and looped and twisted. The seeds have a very hard outer covering. Once released, the seeds retain viability for many years. Like many other Australian plants, the wattle has defences against drought or fire, and needs heat to release seeds or allow them to germinate.
The first leaves from the sprouting seed are always feathery and bipinnate, though later they may change dramatically. Some wattles retain their feathery foliage when adult. Others replace it with leaf-like phyllodes. These are flattened stalks which perform the function of leaves; they are tougher than true leaves and better able to withstand the arid conditions of many parts of Australia.
Foliage ranges from dark to reddish green to greyish green and silvery grey.
The flowers range in colour from cream, pale yellow to deep orange, The flowerhead is made of many small flowers with numerous stamens which create the fluffy appearance. They are massed together in pom-pom heads on short or long stalks or in spikes.
Despite the popularity of native plants in Australian gardens, the growing of wattle has never been widespread. Whilst they are fast growing they do have a short lifespan. They are useful hedge or screen plants.
Wattle is grown from seed. Acacia seed has a very tough coat which must be treated before sowing. For the seed to germinate water must be able to enter the seed. Put the seeds into a dish, pour boiling water over them, leave them overnight, and sow the next day. The boiling water simulates the heat of a bushfire, which prompts wattle germination in the bush. Sow seeds into a 50/50 mix of sand and peat moss. After watering the pot, cover with plastic to create a miniature glasshouse. After the seeds have sprouted remove the plastic and resume watering the seedlings regularly but lightly.
Acacias develop long tap roots very quickly and should be transplanted from the seed bed very early to avoid damage to the roots. In most places autumn is the best time to sow acacias to avoid transplanting in humid weather to prevent fungal attack.
Caring for Wattle
Fertilizers must be used carefully. Some acacias are very sensitive to high levels of phosphorous in the soil.
Acacias respond well to light pruning immediately after flowering to maintain a reasonable shape and to extend life. Wattles can escape from gardens and invade natural areas. For this reason some of the species available commercially may not be the most suitable for home gardens. A careful selection of suitable species should be made. Generally, it is preferable that shrub-sized species be selected. Many wattles will respond to tip pruning after flowering and before new growth commences to maintain a reasonable shape and to extend the life of the plant.
Wattles can be beneficial as garden plants. Because of their fast growth rate and tolerance of full sun, they can provide protection and shelter for other young plants. They also aid the growth of other plants by contributing to the nitrogen content of the soil.
The main pests are borers but galls can be a problem on the smaller branches and on the pods.
The word 'Wattle' is of Anglo-Saxon origin and refers to flexible lengths of branches woven between stakes for the construction of fences or walls, 'wattle and daub' construction, with an additional layer of mud or clay to weatherproof the house walls. The huts of the early settlers were made using this 'wattle and daub' technique. The Acacia branches were found to be the most suitable and these trees soon came to be called Wattles.
Aborigines used the seeds of several species as a source of food. Some species are toxic.
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