Acacia penninervis

Mountain Hickory Wattle, or Blackwood

Family: Fabaceae subfamily Mimosoideae

A variable plant, growing to 8 m tall.

It is widespread, especially in inland areas of Victoria, ACT and NSW. It grows within the entire NSW coastal and tablelands subdivisions, as well as the central and north western slopes and into the north far western plains. It extends into Victoria, as far west as the Melbourne-region. It extends up through the Queensland coast and inland to around Rockhampton. It is an introduced species in New Zealand.

It is typically found in moist and dry sclerophyll forest and woodland, often on sandy to loam soils.

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.

The phyllodes (modified leaves) are glabrous and green/ grey-green with a narrowly oblanceolate or narrowly elliptic shape to 15 cm long and to 4 cm wide (and a lot of variation is observed).

Flowers are produced in globular heads, to 1 cm diameter, with up to 30 very small staminate flowers per head. The heads are clustered in the axils of phyllodes with up to 30 heads per raceme.

Pods can be up to 20 cm long and about 2 cm wide.

In the garden

This is an attractive tall shrub to tree and grows best in full sun with some moisture. It could be easily pruned to a lower height.

Flowers are attractive to bees. It is also known to be a host to the Common Imperial Blue Butterfly.

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

Other information

There are two other varieties both of which have variable phyllodes (shape and size).
Acacia penninervis var. longiracemosa (confined to a few records on the North Coast of NSW).
Acacia penninervis var. penninervis (remainder of range).

Most wattles regenerate from seed after fire, with some species exhibiting suckering from the base.

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.

penninervisLatin refers to the leaf veins arranged regularly on each side of a midrib like barbs from the shaft of a feather; pinnately veined.

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

NSW Flora Online (PlantNET) – Acacia penninervis profile page

Wattle – Acacias of Australia – Acacia penninervis profile page

By Jeff Howes. Editing and additional text by Dan Clarke.