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: Weeping Myall

General Information

Acacia pendula is a tree with a rounded crown and pendulous branches; it can grow from 6 - 13 metres tall. It usually produces a single trunk, which can be 1 - 4 metres tall before branching to produce 2 - 4 ascending main stems[, , ]. Although it produces true leaves as a seedling, llike most members of this section of the genus, the mature plant does not have true leaves but has leaf-like flattened stems called phyllodes[].
The plant is harvested from the wild for local use as a source of materials. It can be used in soil stabilization projects and is grown as an ornamental.
Acacia pendula is a widespread species common on medium to heavy dark riverine soils in New South Wales, Queensland and isolated subpopulations in South Australia and Victoria in Australia. It is also cultivated in other countries. The plant 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 - Victoria, New South Wales, Queensland, South Australia

Habitat

Mainly on floodplains in fertile alluvial clay (and red earth soils in the south of its range), sometimes dominant in woodland and open woodland; at elevations up to 800 metres[][].

Properties

Conservation Status	Least Concern
Medicinal Rating
Other Uses Rating
Habit	Tree
Height	10.00 m
Growth Rate	Medium
Pollinators	Insects
Cultivation Status	Ornamental, Wild

Cultivation Details

Acacia pendula is a plant of the warm temperate and subtropical zones, just entering into the tropics, and is found at elevations up to 800 metres. It grows best in areas where annual daytime temperatures are within the range 20 - 30°c, but can tolerate 4 - 34°c[]. When dormant, the plant can survive temperatures down to about -5°c, but young growth is more tender can be severely damaged at 0°c[]. It prefers a mean annual rainfall in the range 400 - 700mm, but tolerates 250 - 900mm[].
Requires a sunny position. Grows in the wild on heavy clay soils[]. Tolerant of low-fertility soils[]. Prefers a well-drained soil, but trees experience seasonal inundation of the soil in their native habitat[]. Established plants are drought tolerant[]. Prefers a pH in the range 7 - 8, tolerating 6.5 - 8.5[].
Because of its pale, silvery foliage and form of the crown of the tree, this species has been cultivated extensively in Australia and in many other countries including Iran and Kuwait, being grown as a street tree and also used in landscaping[, ].
A fairly fast-growing tree, seedlings can reach 130cm tall within 4 years[].
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[].

Agroforestry Uses:

The tree makes an excellent windbreak, providing shade and shelter[, ].
The tree has a wide-ranging, shallow root system that is excellent for binding the soil but restricts the growth of other species[].

Other Uses

A gum is obtained from the trunk and branches[]. It dissolves entirely in cold water, forming a perfectly clear, almost colourless solution of a brownish tint. Like some other wattle-gums, this would require selecting for the market. There is a marked difference in appearance between the old and new gum of this tree. The new gum is in rounded pieces, and very similar in appearance and usual size to Senegal gum (Senegalia senegal) and Aden gum arabic. The gum which remains long on the trees becomes filled with minute fissures. The fissures, which radiate from the centre of a lump, cause the lump to break into sub-triangular or conical pieces[].
The above report was for Acacia pendula var glabrata - which is currently believed to be a synonym for Acacia melvillei Pedley[, ]. The other reports, below, refer to Acacia pendula, without reference to any variety[].
A good quality gum is obtained from the trunk and branches[].

The oil from fresh cuts emit a pleasant rich violet fragrance that women placed in their garment drawers[].
The tree yields a scented wood, which may have potential for use in perfumery[].

The colour of the wood is a rich, warm brown with darker and lighter streaks. It is close-grained, heavy, very hard, and possesses a highly aromatic scent, but not the same as that of Acacia acuminata (q.v.), for which wood it has sometimes been mistaken. It is very suitable for turnery, as it makes splendid handles of all kinds for bowls, mauls, etc[, ].
The tree's heartwood colour of deep chocolate brown to dark toffee orange, coupled with its peculiar fragrance of violets which can remain for many years, has drawn the interest of fine wood working craftsman for the manufacturing of furniture, fancy boxes etc[, ].
The wood is used for fuel[].

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[].