Acacia obtusata

Blunt-leaf Wattle, Obtuse Wattle

Family: Fabaceae subfamily Mimosoideae

Acacia obtusata is a shrub, growing with a spindly habit up to 3 m tall and 2 m wide.

It grows in NSW on the central and southern tablelands and western edges of coastal subdivisions, from Rylstone-district to near Braidwood across to Tumut. It is common in the western Blue Mountains.

Its habitat is chiefly dry sclerophyll woodland and forest.

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 species belongs to Group 1.

The phyllodes (resemble leaves) have an oblanceolate or sometimes narrowly elliptic shape with reddish new tips, to 11 cm in length with a width of up to 1.5 cm, somewhat blue-grey in colour.

Flowers are produced in globular heads with up to 25 very small staminate flowers per head. Heads are to about 7 cm diameter, bright-yellow in colour, and arranged in racemes of up to 14 heads, in the leaf axils.

The seed pods have a length of 10 cm by about 1 cm wide.

In the garden

Not commonly grown in cultivation. It may be hard to source at local native nurseries.

Grows best in well-drained soils in full sun. Is fast growing and makes an excellent informal windbreak or hedge in cultivation. Hardy once established. Tolerates sandy loam to clay loam soils with good drainage.

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

Most wattles will die in a fire and regenerate from seed. Some species exhibit suckering from basal parts and roots.

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.

obtusata – Latin – named in reference to the blunted (obtuse) tips of the phyllodes.

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

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

Wattle – Acacias of Australia – Acacia obtusata profile page https://apps.lucidcentral.org/wattle/text/entities/acacia_obtusata.htm

December 28, 2020