An erect or spreading tree with a wide range of cultivated forms; a shrub from 1 to 10 m tall, with pendulous branchlets.
It is found in dry sclerophyll forest and woodland in sandstone and granite-derived soils, generally south from Nowra in NSW, with most of its extent concentrated on the south coast subdivision, extending into the southern tablelands. However, there are also records at Pokolbin in the Hunter Valley. It extends into Victoria, growing mainly in the eastern corner as far west as Orbost.
Australian Wattles at least, can be broadly placed into 1 of 3 recognisable groups:
It is thought that Groups 1 and 2 are more highly evolved than Group 3.
This species is of Group 1: phyllodes (modified leaves) are linear and very narrow, slightly curved, to 10 cm long and only 0.4 cm wide, dotted with resin glands, often sticky, with a mucro at the apex. Overall, the foliage has a weeping, delicate appearance.
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, conspicuously staminate flowers are arranged in globular heads, to 6 mm diameter, with up to 25 very small staminate flowers per head. Pale lemon in colour. Heads are produced solitarily or in pairs in phyllode axils, creating sprays up and down the plant.
Pods straight, and flat, raised over seeds, to 10 cm long and 0.4 cm wide.
One of the most foremost and popular wattles to be grown, especially the compact dwarf cultivars ‘Limelight’ and ‘Bower Beauty’ (amongst others) and the tree cultivar ‘Lime Magik’.
Very hardy, can be used in formal gardens, planted in a row or used as a hedge. Great gap-filling plant and to create rounded structure (dwarfs forms). Tree-forms are very attractive with weeping foliage.
Prefers full sun to semi shade and tolerates moderate frost.
Hardy in a range of soils, but give good drainage to thrive. A slight slopes works very well. Prune to shape to that desired.
It is fast growing and has a useful life of 5 to 10 years. Plan to replaces after 5 years.
Used in a wide range of landscapes. Some species like ‘Limelight’ and ‘Waterfall’ are available as grafted standards.
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.
Cultivated forms need to be propagated from cuttings.
As stated above, cultivars include: ‘Limelight’, ‘Bower Beauty’, ‘Green Mist’ (dwarf forms) and others. The dwarf forms grow to generally less than 1 m tall but can spread wider, and usually create a dense coverage over the ground.
The taller shrub/tree forms are “Lime Magik’, ‘Cousin It’, ‘Waterfall’, ‘Copper Tips’ and there are others.
Some of the smaller ones include ‘Green Mist’, ‘Mini Cog’, ‘Fettucine’ and ‘Bower Beauty’.
Most wattles regenerate from seed after fire with some species exhibiting suckering from the base.
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.
cognata – meaning cognate – “being related by kinship or common origin”; as it is thought to be closely related and similar to Acacia subporosa, a NSW south coast species.
Not considered at risk in the wild.
NSW Flora Online – Acacia cognata profile page https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Acacia~cognata
Gardening with Angus – Acacia cognata profile page https://www.gardeningwithangus.com.au/acacia-cognata-limelight-river-wattle/
Mallee Design – Acacia cognata page
Wikipedia – Acacia cognata profile page
Wrigley, J.W. & Fagg, M.I. (2001). Australian Native Plants – Propagation, cultivation and use in landscaping. 4th edition. New Holland Publishers, Pty. Ltd. Australia.