This is a shrub or erect or spreading tree from 2 to 16 m high, depending on moisture conditions, goorwing smaller in dry soils. It has a medium domed canopy.
Acacia binervia is found in central New South Wales from the Hunter Region south, and to Bungonia in the southwest, and continuing south into Victoria.
It grows in dry sclerophyll forest or heath on rocky slopes, often near streams. It is common in Sydney along the banks of the Georges River on alluvial sands. It also grows in places like the rocky ocean-side hills at Nelson Bay.
The rough bark is dark brown to grey in colour, fibrous to flaky.
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 2. The phyllodes are elliptic to sickle-shaped (falcate) to 6 to 15 cm long and about 2 cm wide; and are a striking blue-grey colour, with 2, 3 or 4 parallel veins.
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 cylindrical pale to bright yellow spikes of flowers, to 6 cm long, are very showy and appear in spring from August to October.
The fruit is a pod – to 8 cm long.
This is a fast growing tree and lives for around 25 years. It is an attractive small tree with flowing blue green foliage.
It prefers full sun to semi shade and tolerates 2nd line salt and light frost. Its best in deep fertile soils with reliable moisture though can tolerate periods of drought once established.
Early shaping of the tree will help establish a single trunk and raised canopy.
The flowers are useful to bees in the honey industry.
It is useful as a screen, windbreak or specimen plant and is suitable for coastal locations.
The flowers can be spectacular in some seasons.
Acacias can suffer from a number of pests, including borers, scale, galls and leaf miners. Growing plants suitable to your local environment minimises these pests occurring.
The foliage is reported to be toxic to stock, the phyllodes containing a glucoside which may produce prussic acid when severed.
Propagation is easy done from scarified seed by covering with boiling water for 24 hours and discarding any seeds still floating on the surface.
It is often sold under the common name of ‘Silver Spray’.
This species regenerates readily from bushfire through the soil seedbank.
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.
binervia – refers to the phyllodes having 2, or usually 3-5, prominent longitudinal veins.
Just note that there is also a coastal species in NSW named Acacia binervata which is also a small tree but has really prominent 2-veined phyllodes which are green-grey.
It is not considered to be at risk of extinction in the wild.
NSW Flora Online (PlantNET) – Acacia binervia profile page: http://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Acacia~binervia
Wikipedia – Acacia binervia profile page: https://en.wikipedia.org/wiki/Acacia_binervia
Wrigley, J.W. & Fagg, M.I. (2001). Australian Native Plants – Propagation, cultivation and use in landscaping. 4th edition. New Holland Publishers, Pty. Ltd. Australia.