Acacia longifolia is commonly known as the Sydney Golden Wattle, and is a tall shrub or small tree that may reach a height of 6 to 7 metres, typically with a wide spread if planted out in the open.
It is a beautiful wattle with a wide distribution and is found in coastal districts from Queensland to northeast Victoria. Populations also extend into the Northern Tablelands of NSW. It is found in foredunes and part of sclerophyll woodland or coastal heath and scrub communities. In Western Australia, however, it is a serious weed and has seriously affected some coastal habitat there.
Australian Wattles at least, can be broadly placed into 1 of 3 recognisable groups:
Phyllodes and bipinnate leaves are always alternate to clustered, never opposite.
This wattle belongs to Group 2.
The phyllodes are flat, up to 18 centimetres long, to 3 cm wide with several longitudinal veins and a small gland near the base, mid-green in colour. Phyllodes can be variable between trees and populations.
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, bright golden-yellow staminate flowers are carried in spikes with a pair of spikes at the base of each phyllode, to about 5 cm long by 8 mm wide. In late winter and spring the blooms are both conspicuous and profuse.
Straight or curved pods follow the flowers and hold many seeds.
This wattle grows best in full sun. It tolerates shade, but its foliage will be less dense. It tolerates salt, wind and some frost.
It prefers well drained soils and performs well on sandy soils. It tolerates some periods of drought. It is good in coastal gardens, as a windbreak or screen. It also provides habitat for birds and insects. Heavily-flowering plants can be are covered in European Honeybees
It has a useful life of about 10 years. A light prune after flowering will assist in keeping it bushy with prolific flowering.
Propagate from seed that should be treated with boiling water before sowing.
Acacia longifolia is widely cultivated in subtropical regions of the world for various uses including prevention of soil erosion, food and dye from the flowers and bark. In some areas, it has become a major weed.
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.
longifolia – Latin – referring to long leaves.
This species is not considered to be at risk of extinction in the wild.
NSW Flora Online (PlantNET) – Acacia longifolia profile page. https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl%26lvl=sp%26name=Acacia~longifolia
EFlora SA – Electronic Flora of South Australia – Acacia longifolia fact sheet http://www.flora.sa.gov.au/cgi-bin/speciesfacts_display.cgi?form=speciesfacts&name=Acacia_longifolia%20var.%20sophorae
Wrigley, J.W. & Fagg, M.I. (2001). Australian Native Plants – Propagation, cultivation and use in landscaping. 4th edition. New Holland Publishers, Pty. Ltd. Australia.
Wikipedia, Acacia longifolia profile page
https://en.wikipedia.org/wiki/Acacia_longifolia