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Acacia melanoxylon

Blackwood, Hickory, Mudgerabah, Tasmanian Blackwood, or Blackwood Acacia

Family: Fabaceae subfamily Mimosoideae

Acacia melanoxylon is a tree growing to 30 m tall.

In NSW, it is commonly encountered up and down the coast, tablelands and it is scattered on the western slopes. It extends into Queensland, as far north as Cairns in scattered occurrences. It grows through most of Victoria and Tasmania and extends as far west as the Adelaide-region and northwards, in South Australia.

It is found in a variety of habitats, chiefly in wet and dry sclerophyll forest and woodland, and in or near cooler rainforest.

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).

This wattle belongs to Group 1.

Phyllodes (modified leaves) are narrowly elliptic to oblanceolate, to 14 cm long and 3 cm wide.

Flowers are firstly arranged into globular heads, to 10 mm diameter, with each head having up to 50 very small staminate flowers, pale yellow to white. The heads are grouped into racemes, emerging from the leaf axils with up to 8 heads per raceme, occurring in July to December.

Seed pods are strongly curved or twisted or coiled, to 12 cm long and about 1 cm wide.

In the garden

Ornamentally it is an attractive feature or shade tree in broad streetscapes, reserves and parks. Long lived and attracts birds, native butterflies and insects. Is also a caterpillar food plant. Adaptable to most soils and needs moderate watering. Can grow to a large tree but in a garden it can be pruned to a medium to large shrub.

Acacias can suffer from a number of pests, including borers, scale, galls and leaf miners. Growing plants suitable to your local environment minimises these occurring.

Propagation

Propagation is easy from scarified seed by covering with boiling water for 24 hours and discarding any seeds still floating on the surface.

Other information

First Nations People of Australian derive an analgesic from the tree. It was also used to make spear throwers and shields.

It is a declared noxious weed species in South Africa and is a pest in Portugal’s Azores Islands. Even in some regions of Tasmania, blackwood is now considered a pest.

Acacia melanoxylon is valued for its decorative timber which may be used in cabinets, musical instruments and in boatbuilding.

Will regenerate from seed after fire as well as basal suckering.

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.

melanoxylon – from the Ancient Greek roots melās, meaning “dark” or “black” and xylo (ξύλο), meaning “wood”.

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

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

VICFlora (Flora of Victoria Online) – Acacia melanoxylon profile page https://vicflora.rbg.vic.gov.au/flora/taxon/a7b5e691-0803-40d6-a1d4-dd96e54720a0

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 Jeff Howes. Editing and additional text by Dan Clarke.