Acacia longifolia subsp. sophorae is a prostrate to large shrub to 2-3 metres in height.
It grows purely very close to the coast, from south-east Queensland to South Australia, including Tasmania, usually on sand dunes. It has become a weed in western Victoria and SA. It tends to be prostrate to decumbent when growing on exposed coastal dunes, but may grow as a large shrub (sometimes taller) in more sheltered locations such as near-coastal forests.
Currently, it is treated as a subspecies of Acacia longifolia in NSW, which is usually a much taller plant with more elongated phyllodes. But is considered a separate species by other botanists.
Australian Wattles at least, can be broadly placed into 1 of 3 recognisable groups:
This wattle belongs to Group 2.
The phyllodes (modified leaves) are elliptic to obovate, to 11 cm long and to 3 cm wide with prominent longitudinal veins, light to mid-green in colour.
The bright yellow flowers are produced in linear spikes, to about 5 cm long and about 0.6 cm wide, occurring in the axils of the phyllodes (1 or 2 per axil). Flowering is mainly in late winter and spring.
Seed pods often coiled and twisted on opening, to potentially 20 cm long by 0.6 cm wide.
A hardy plant in a wide range of habitats and soil types provided they are not waterlogged. A position in full sun or light shade is suitable and the species is tolerant of at least moderate frosts. Suitable for coastal plantings. Can make a solid ground cover if the form obtained is prostrate.
A. longifolia subsp. sophorae has become an environmental weed in some areas (eg. western Victoria and South Australia).
Care should be exercised in planting these species in areas close to bushland.
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.
Most wattles regenerate from seed after fire, with some species exhibiting suckering from the basal areas.
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.
longifolia – Latin meaning long-leaves.
subsp. sophorae – similar to some species in the genus Sophora – a genus of peas (Fabaceae subfam. Faboideae) which are spread worldwide.
This taxon is not considered to be at risk of extinction in the wild.
NSW Flora Online (PlantNET) – Acacia longifolia subsp. sophorae profile page https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=in&name=Acacia~longifolia~subsp.+sophorae
Friends of Venus Bay Peninsula Inc – Acacia longifolia subsp. sophorae plant of the month profile page https://friendsofvenusbaypeninsula.org.au/wp-content/uploads/2017/08/Coastal-Wattle-Acacia-longifolia-subsp.-sophorae.pdf
Wrigley, J.W. & Fagg, M.I. (2001). Australian Native Plants – Propagation, cultivation and use in landscaping. 4th edition. New Holland Publishers, Pty. Ltd. Australia.
Australian Native Plants Society of Australia – Acacia longifolia subsp. sophorae profile page https://anpsa.org.au/plant_profiles/acacia-longifolia/