Classification of the genus Acacia (in the wider sense) has been subject to considerable debate. It is generally agreed that there are valid reasons for breaking it up into several distinct genera, but there has been disagreement over the way this should be done. As of 2017, it is widely (but not completely) accepted that the section that includes the majority of the Australian species (including this one) should retain the name Acacia, whilst other sections of the genus should be transferred to the genera Acaciella, Mariosousa, Senegalia and Vachellia[].

Common Name:

General Information

Acacia linearifolia is a shrub or a tree with a usually narrow crown; it usually grows around 10 metres tall, but can reach 14 metres in favourable sites. The bole is usually straight and can be 15 - 45cm in diameter[]. Although it produces true leaves as a seedling, like most members of this section of the genus, the mature plant does not have true leaves but has leaf-like flattened stems called phyllodes. This species, however, often retains some true leaves on its lower branches[].
The plant is regarded as having good prospects as a crop plant for high volume wood production. It is often grown as an ornamental in Australia.
Across the range of this species there has been historic land conversion from native forests to agricultural land. However, no specific threats have been identified, the species is found in some protected areas and it also has a large range It is classified as 'Least Concern' in the IUCN Red List of Threatened Species(2013)[].

Known Hazards

Especially in times of drought, many Acacia species can concentrate high levels of the toxin Hydrogen cyanide in their foliage, making them dangerous for herbivores to eat.

Botanical References

Range

Australia - southeastern New South Wales

Habitat

Temperate forests, where it grows commonly in colluvial sand on lower slopes of sandstone hills; growing at elevations up to 650 metres[, ].

Properties

Conservation Status	Least Concern
Medicinal Rating
Other Uses Rating
Habit	Tree
Height	8.00 m
Growth Rate	Fast
Pollinators	Insects
Cultivation Status	Cultivated, Ornamental

Cultivation Details

Acacia linearifolia is native to the semi-arid to sub-humid regions of the warm temperate zone of eastern Australia, where it can be found at elevations up to 650 metres. It grows best in areas where the mean maximum temperature of the hottest months can reach 21 - 32°c, and the mean minimum in the coldest month can fall to 2 - 3°c. The plant can often experience moderate frosts, down to around -5°c for short periods. Whilst older plants can resist this, young plants can often be damaged, though they usually revocer well. Mean annual rainfall can vary from 540 - 720mm, with a variable dry season that can range from 0 - 6 months[].
Requires a sunny position in a well-drained soil.
The plant appears to grow quickly when young and probably lives for around 20 - 30 years[].
Plants growing in an area with a mean annual rainfall of 620mm, and estimated to be about 10 years old, attained a height of 10 - 12 metres with stems 20 - 26cm in diameter[].
Acacia linearifolia is well suited as an ornamental on account of its attractive growth form and its prolific flowering - it is often grown for this purpose in eastern Australia[].
The plant is not known to produce suckers, but responds well to coppicing[].
This species has a symbiotic relationship with certain soil bacteria; these bacteria form nodules on the roots and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby[].

Edible Uses

None known

Medicinal

The bark of all Acacia species contains greater or lesser quantities of tannins and are astringent. Astringents are often used medicinally - taken internally, for example. they are used in the treatment of diarrhoea and dysentery, and can also be helpful in cases of internal bleeding. Applied externally, often as a wash, they are used to treat wounds and other skin problems, haemorrhoids, perspiring feet, some eye problems, as a mouth wash etc[, ].
Many Acacia trees also yield greater or lesser quantities of a gum from the trunk and stems. This is sometimes taken internally in the treatment of diarrhoea and haemorrhoids[].

Other Uses

The wood is likely to have similar properties to Acacia neriifolia, which has a mid-brown heartwood and pale yellow sapwood, with an attractively marked, close-grained and tough wood[].

Propagation

Seed - best sown as soon as it is ripe in a sunny position in a warm greenhouse[].The dried seed of most, if not all, members of this genus has a hard seedcoat and may benefit from scarification before sowing to speed up germination. This can usually be done by pouring a small amount of nearly boiling water on the seeds (being careful not to cook them!) and then soaking them for 12 - 24 hours in warm water. By this time they should have imbibed moisture and swollen - if they have not, then carefully make a nick in the seedcoat (being careful not to damage the embryo) and soak for a further 12 hours before sowing. Sow the seed in Spring in a greenhouse. As soon as the seedlings are large enough to handle, prick them out into individual pots and grow them on in a sunny position in the greenhouse for their first winter. Plant them out in late spring or early summer, after the last expected frosts, and consider giving them some protection from the cold for their first winter outdoors.
Acacia seeds that have matured fully on the bush and have been properly dried have a hard seed coat and can be stored in closed containers without deterioration for 5 - 10 years or more in dry conditions at ambient temperatures. It is best to remove the aril, which attracts weevils and can lead to moulds forming. The arils are easilyremoved by placing the seeds in water and rubbing them between the hands, then drying the seeds and winnowing them[].