Acacia longifolia (syn. Racosperma longifolium) | ‘Coastal Wattle’, ‘Sydney Golden Wattle’ | Seeds
Native to Australia, the popular Acacia longifolia (syn. Racosperma longifolium) is a fast-growing perennial tree or shrub of the Fabaceae family. Most commonly known as the ‘Sydney Golden Wattle’, longifolia is also known under many other names, including ‘Acacia à Longues Feuilles’, ‘Acacia Trinervis’, ‘Acácia-de-Espigas’, ‘Acácia-de-Folhas-Longas’, ‘Aroma Doble’, ‘Coastal Wattle’, ‘Gaggia a Foglie Lunghe’, ‘Golden Rods’, ‘Golden Wattle’, ‘Kätzchen’, ‘Langblaarwattel’, ‘Langblättrige’, ‘Long-leaved Acacia’, ‘Mimosa Chenille’, ‘Mimosa de Flores Amarelas’, ‘Sallow Wattle’, ‘Swallow Acacia’, ‘Sydney Acacia’ and ‘White Sallow’.
Acacia longifolia grows as a spreading shrub or small erect tree, ranging from two metres to ten metres high and spreading two metres to twenty metres wide. As with many related Acacia species, instead of leaves the plant produces smoothly pliable, linear to elliptic phyllodes, between five and twenty-five centimetres long and ten to thirty millimetres wide. Longifolia’s beautifully fragrant, lemon-yellow flowers are two centimetres to five centimetres long and are followed by cylindrical or semi-cylindrical seedpods. Pollination is often by bees and other insects, such as Apis mellifera. The seedpods are five to fifteen centimetres long and five millimetres to ten millimetres wide and can produce anything up to around eleven thousand seeds each year, with seed dispersal effected mainly by ants, birds, rodents, soil and water.
Two subspecies are described within Acacia longifolia, subsp. longifolia and subsp. sophorae – although some consider these distinct species, Acacia longifolia and Acacia sophorae. Very generally, sophorae is roughly half the size of longifolia once mature and forms thicker, more brittle phyllodes and more irregularly-shaped seedpods. The species as a whole is closely related to Acacia floribunda and Acacia maidenii.
Like many Australian Acacia, the species and its products have found practical applications in many areas. Examples of these include longifolia’s use in agroforestry and revegetation, as charcoal or fuelwood, as cut flowers, as dyestuffs or tanning agents, for erosion control or dune stabilisation, as food source (the seeds have a low glycaemic index and contain roughly 26% protein, 26% available carbohydrate, 32% fibre and 9% fat), for grafting stock, as timber, for its gum, as nitrogen-fixer and as an ornamental or landscaping tree. The plant is further recommended (along with the closely-related species Acacia melanoxylon) for use as a cheap replacement compost to pine bark, in combination with other organic materials, such as peat moss.
Growing naturally in full sun in USDA Climate Zones 10 and 11, longifolia’s preferred habitats are sandy coasts and dunes, but it also thrives across bushland, littoral and natural forests, agricultural land, rail culverts and roadsides, riparian zones, riverine areas and scrub and grasslands too. Contributing to this ability to excel in almost any environment, the ‘Sydney Golden Wattle’ is both drought and saline-resistant, capable of growing in nutrient-poor media and well-adapted to fire. It does best on light well-drained sandy loam, whether acid, neutral or basic, but can’t tolerate strong shade or wind. The mean annual temperature should be between 10ºC and 25ºC; 10ºC to 19ºC is ideal.
Longifolia is an easy tree to grow from seed and viability remains high (roughly ninety percent) even after years of storage. Illustrating this longevity, some tests demonstrated 12% germination after “fifty years of open storage at room temperature”! Suitable pre-treatment and a warm climate offer the best chances, greatly increasing the germination rate of this fantastic Wattle.
A fast-growing and low-maintenance species, it’s known as the ‘Golden Wattle’ for good reason, so why not sow some great Acacia longifolia seed today!
All the seed sold by Arkham’s Botanical was freshly and ethically sourced in 2018-2019