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Acacia dealbata

Silver Wattle

Family: Fabaceae subfamily Mimosoideae

Acacia dealbata, Silver Wattle, develops into a medium-sized tree that will reach a height of 30 metres, although often seen much smaller in NSW.

A. dealbata is a very widespread species in NSW, occurring over most of the tablelands and western slopes regions. It extends into Victoria, growing over most parts except the north-west and grows over most of Tasmania (where large specimens can be found).

Bark is smooth, grey-brown to dark grey and becomes fissured with age.

Australian Wattles at least, can be broadly placed into 1 of 3 recognisable groups:

  • Group 1: Those that produce juvenile compound-bipinnate leaves and then change to producing adult-phyllodes which are modified-flattened petioles which form the foliage. This is combined with flowers produced in globular balls or heads (or ovoid heads). The heads can be singular in leaf/phyllode axils or arranged in groups.
  • Group 2: As for Group 1 but flowers are produced in longer rod-like spikes.
  • Group 3: Those that never produce phyllodes and retain the juvenile compound-bipinnate foliage into adulthood. These always produce flowers in globular balls (which are secondarily arranged into panicle or raceme-like groups in many cases).

It is thought that Groups 1 and 2 are more highly evolved than Group 3.

This species is of Group 3: Bipinnate foliage is bluish-grey, this coupled with the whitish appearance of the branchlets gives the species its common name. There is a gland at the junction of each pair of pinnae and the rachis.

Acacia spp. produce small 5-merous flowers, with 5 very small petals partly-fused into a short tube which sits above a fused calyx. The stamens are the main feature which are produced in high numbers per flower (staminate flowers), surrounding a single style.  In this species, the flowers are held in globular clusters with 25-35 bright yellow flowers in each cluster. Heads are arranged into raceme-like groups which create a very attractive display. Blooms are carried from late winter to spring.

Pods are straight to curved, to 12 cm long and about 1.5 cm wide.

In the garden

Silver Wattle is a handsome, long-lived tree. Foliage and flowers are attractive features. The species is probably too large for a suburban garden but would make an ideal component in a rural shelterbelt or windbreak on farms. Silver Wattle could also be used as an avenue tree lining the entrance to a rural property.

There is a ground covering form known as “Kambah Karpet”. A specimen is growing in the National Botanic Gardens, Canberra.

Propagation

Propagate from seed that should be soaked in boiling water before sowing.

Other information

Silver Wattle is also grown in Europe where it is known as Mimosa. Sprays of flowers are given out to celebrate Mothers Day.

Gum Arabic is produced from the hardened sap that exudes from the trunk. Bark was used for tanning leather and the foliage is used for dyeing.

Silver Wattle is a timber of choice for furniture designers because of its attractive figure and ready workability. It affords a striking visual contrast to A. melanoxylon (Blackwood), a closely related species.

Silver Wattle is grown in Europe where it is known as “Mimosa”. Sprays of flowers are given out to celebrate Mothers Day. In Italy, Albania, Russia and Georgia, the flowers are often given to women on International Women’s Day. The flower essence is used in perfumes. Leaves are sometimes used in Indian chutney.

This species will regenerate from seed after fire and may sucker from rootstocks, producing dense stands.

Acacia is a highly diverse genus, with over 1500 recognised species (placing it in the top-10 most-diverse plant genera) occurring in most continents except for Europe. Australia has about 970 spp., most of which are endemic. There are also about 10 exotic species. NSW has about 235 recognised species. Some species have become weeds in other states outside of their natural range (e.g., wattles from Western Australia into NSW and vice versa).

Acacia – from Greek Akakia – which refers to an Ancient Greek preparation made from one of the many species; the name of which derives from akis, meaning “thorn” – referring to the thorns of species in Africa.

dealbata – Latin meaning “whitened” or “white-washed” – referring to the white waxy-resin or material on the branches and stems; a term referred to as pruinose.

This species is not considered to be at risk of extinction in the wild.

NSW Flora Online (PlantNET) – Acacia dealbata profile page                         https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Acacia~dealbata

Wikipedia – Acacia dealbata profile page                                    https://en.wikipedia.org/wiki/Acacia_dealbata

Wrigley, J.W. & Fagg, M.I. (2001). Australian Native Plants – Propagation, cultivation and use in landscaping. 4th edition. New Holland Publishers, Pty. Ltd. Australia.

By Warren and Gloria Sheather. Editing and additional text by Dan Clarke.