Acacia rupicola

Rock Wattle

Family: Fabaceae subfamily Mimosoideae

The Rock Wattle is a rigid, upright shrub that reaches a height of two metres and has slightly sticky foliage and stems.

Acacia rupicola is found in western Victoria, extending west along the coast of South Australia, to about Streaky Bay.

It is listed as threatened with extinction under Victorian legislation.

It grows in dry sclerophyll woodland and shrublands, often on rocky soils. (Rock Wattle is an appropriate common name because the species name means “of rocky areas”).

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.

Phyllodes are about two centimetres long with a single vein, with a pungent point (sharply pointed) and a gland near the base. Young foliage and buds are resinous.

Very small staminate flowers are produced in globular heads, cream to yellow, with up to 25 flowers per head, with heads produced solitarily in the leaf axils; appearing from August to January with sporadic flowering at other times.

Pods are linear to about 7 cm long by 0.5 cm wide.

In the garden

The Rock Wattle would be a colourful addition to native shrubberies. Just keep plants away from the borders as the foliage is a trifle prickly. It is reported to be cultivated and grows well on a well-draining light soil. Prune to shape after flowering.

Reported to attract Double-spotted Lineblue butterflies.

Propagation

Propagate from seed (pre-treated with boling water or scarified) and cuttings.

Other information

The type specimen was collected in the Marble Range, southern South Australia.

Acacia rupicola is similar to the well-known Acacia ulicifolia (Prickly Moses) group of wattles but is distinguished from them by its sticky appearance.

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.

rupicola – Latin – translating to “living near rocks”.

This species is listed as threatened with extinction in Victoria with the category of Endangered.

VICFlora – Flora of Victoria Online – Acacia rupicola profile page https://vicflora.rbg.vic.gov.au/flora/taxon/f340e887-251f-4256-91eb-6c2abad3b388

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

Botanic Gardens of South Australia – Plant Selector – Acacia rupicola profile page http://plantselector.botanicgardens.sa.gov.au/Plants/Details/2849

May 25, 2020