- Mature height
- 6m to 10m
- Mature width
- 4m to 6m
Acacia mearnsii is one of the fastest-growing trees available in Australia, adding up to 1.2 metres a year to establish shelter, screening or canopy cover in a fraction of the time any other species would take. Fine feathery dark green foliage carries masses of fragrant golden flowers through spring and summer.
Black Wattle grows to 6 to 10 metres tall and 4 to 6 metres wide, forming a dense spreading canopy. It is a classic pioneer species, used to stabilise disturbed ground, provide quick shelter for slower long-term plantings, and fix nitrogen into depleted soils on rural and revegetation sites.
This Australian native is frost hardy, surviving heavy and frequent frost without damage, and tolerates poor soils and extended dry once established. Like most fast wattles it is short-lived at 15 to 25 years, which suits its role as a nurse crop rather than a permanent tree.
Frequently Asked Questions
About Acacia mearnsii
How fast does Acacia mearnsii grow?
Very fast, at 80 centimetres to 1.2 metres per year. It is among the quickest trees available in Australia for establishing shelter or canopy cover.
How big does Black Wattle grow?
Acacia mearnsii reaches 6 to 10 metres tall and 4 to 6 metres wide, forming a dense spreading canopy suited to windbreaks and shelterbelts.
How long does Acacia mearnsii live?
It is short-lived at 15 to 25 years, which is typical of fast pioneer wattles. Plant it as a nurse crop to shelter slower long-term species rather than as a permanent tree.
When does Black Wattle flower?
Masses of fragrant pale golden ball flowers appear through spring and into summer, attracting bees, native pollinators and insect-feeding birds.
Does Acacia mearnsii improve soil?
Yes. Like other wattles it fixes atmospheric nitrogen through root nodules, which improves depleted and disturbed soils. This makes it valuable in revegetation and mine-site rehabilitation.
Is Black Wattle frost hardy?
Yes. It is frost hardy and survives heavy and frequent frost without damage, performing well in cold inland and tablelands districts.
How far apart should I plant Acacia mearnsii for a windbreak?
Plant 2 to 3 metres apart for a dense shelterbelt, or 4 to 6 metres apart where individual canopies should develop fully.