Longleaf Wattle

Acacia longifolia is a shrub or erect, spreading tree that typically grows to a height of 1–10 m (3 ft 3 in – 32 ft 10 in) and has glabrous branchlets and smooth or finely fissured grey bark. Its phyllodes are straight or slightly curved, 40–250 mm (1.6–9.8 in) long, 10–35 mm (0.39–1.38 in) wide, with two to four prominent veins, a gland 3–8 mm (0.12–0.31 in) above the pulvinus, and sometimes a small point on the end. Its flowers are golden yellow, sometimes paler, and borne in one or two mostly sessile spikes 20–50 mm (0.79–1.97 in) long in axils. Flowering occurs between June and October, and the pods are mostly cylindrical, straight to strongly twisted, sometimes appearing like a string of beads, 50–150 mm (2.0–5.9 in) long, 3–6 mm (0.12–0.24 in) wide, thinly leathery or firmly papery and brittle when dry. The seeds are elliptic, 4–6 mm (0.16–0.24 in) long and shiny with a large, skirt-like aril.

This species of Acacia is native to southeastern Australia, from the extreme southeast of Queensland, through eastern New South Wales, eastern and southern Victoria, southeastern South Australia, and Tasmania. The species is endemic to coastal area of south eastern Queensland close to the border with New South Wales extending southward down the coast of New South Wales. In New South Wales it is common along the tablelands and coastal areas where it grows in various habitats including foredunes and in sclerophyll woodland or coastal heath and scrub. The range then extends south and east through Victoria and into South Australia, where it is found on the Eyre Peninsula, Yorke Peninsula, Kangaroo Island, southern Mount Lofty Ranges, and throughout the south-eastern region, where it is mostly restricted to sand dunes. The subspecies, sophorae, grows in sand dunes around the Tasmanian coastline. It has become naturalised in the south west of Western Australia in coastal areas extending from around Perth in the north down to around Albany in the south. It is thought to have been introduced by escaping from gardens or being used in revegetation plantings. Control methods include hand pulling seedlings, ringbarking, or cutting the plant down and painting the stump with glyphosate.

Acacia longifolia is widely cultivated in subtropical regions of the world. Its uses include prevention of soil erosion, food (flowers, seeds and seed pods), yellow dye (from the flowers), green dye (pods) and wood. The flower colour derives from the organic compound kaempferol. The tree's bark has limited use in tanning, primarily for sheepskin. It is useful for securing uninhabited sand in coastal areas, primarily where there are not too many hard frosts. In Tasmania the ripening pods were roasted and the seeds removed and eaten.

Kaempferol (3,4′,5,7-tetrahydroxyflavone) N-(2-imidazol-4-yl-ethyl)-trans-cinnamamide N-(2-imidazol-4-yl-ethyl)-deca-trans-2, cis-4-dienamide Dimethyltryptamine 0.2–0.3% & Histamine

Despite its weed potential outside its normal range, the shrub is available commercially and can be propagated by seed scarification or boiling water treatment. It is regarded as an attractive, hardy, fast-growing species suitable as a hedge plant or for screening. Suitable for hydroseeding work on banks where it will provide soil stabilization. Sydney golden wattle is well suited for low maintenance areas such as road batters, will grow in a range of soil types and is frost hardy. It is heavily used at present in Southern California as a street canopy tree, as it grows fairly quickly (reaching a height of five meters within a year or two of planting), tolerates drought, and is resilient even to the particularly brutal pruning practices associated with low-cost tree services. In Portugal the species is considered highly invasive in sand dunes, and its cultivation is prohibited by law.