Acacia, yellow flowers of Australia

The Acacia is a tree with brilliant yellow flowers. They are found mostly in Australia. Among the species in the Acacia genus include Acacia dealbata (@ Mimosa, @ Silver Wattle), Acacia longifolia (Coast Wattle or Sydney Golden pattle), Acacia mearnsii (Black Wattle), and Acacia melanoxylon (Blackwood), can be found as south as Tasmania, Australia, while Acacia caven (Espinillo Negro) can be found as far south as Chubut Province of Argentina. Australian species are usually called wattles, while African and American species are usually called acacias.

A few species of Acacia are also found in the Sinai desert and the Jordan valley including Acacia albida, Acacia tortilis and Acacia iraqensis.

The leaves of most acacias are compound pinnate. In many species particularly those found in the Australian and Pacific islands species, the leaflets are suppressed. These are known as phyllodes. The vertical orientation of the leaflets protects them from intense sunlight. With their edges towards the sky, they do not get as much light as horizontally placed leaves. Some species including Acacia glaucoptera do have have leaves or phyllodes at all. Instead, they possess leaf-like photosynthetic stems functioning as leaves which are called cladodes.

The small flowers of the Acacia have five very small petals. The flowers are arranged in globular or cylindrical clusters. Acacia flowers are usually yellow or cream-colored in most species, and whitish in some. Acacia purpureapetala has purple flowers while Acacia leprosa Scarlet Blaze has red flowers.

Acacia trees produce a number of organic compounds that ward off pests and grazing animals. However, many Acacia species in Australia are sometimes used as food plants by the larvae of hepialid moths. The larvae burrow into the trunk, first horizontally and then vertically down. In general however, Acacias are usually trouble free from pests and diseases.

Many species of acacia produce gum. Gum arabic, for example, comes from Acacia senegal, growing abundantly in West Africa from Senegal to northern Nigeria. Acacia arabica, from India, also produces gum, but is inferior to the true gum-Arabic.

The most popular acacia for gardens is Acacia dealbata (Silver Wattle). It has glaucous to silvery leaves and bright yellow flowers. It is often mistakenly called "mimosa", a confusion with the related genus Mimosa. Another ornamental acacia is Acacia xanthophloea (Fever Tree). In Southern Europe, florists use Acacia baileyana, Acacia dealbata, Acacia pycnantha and Acacia retinodes as cut flowers. Over there, the common name used to refer to them is also mimosa.

The sharp thorns of some species help to enhance home security. By planting it near windows and drainpipes, it helps to prevent break-ins. The beauty of acacia makes it an attractive alternative to erecting a fence or wall.

Botanical Name Abies
Planting condition In full sun, in neutral to acid soil
Propagation By seed in spring, semi-ripe cuttings in summer
Pests and diseases Usually pest free

Acacia Photo Album

Acacia alataAcacia alata
Author: PDG (GFDL)

Acacia acinaceaAcacia acinacea
Author: Danielle Langlois (GFDL)

Acacia aphylla, Leafless Rock Wattle
Acacia aphylla, Leafless Rock Wattle
Author: Danielle Longlois (GFDL)

Acacia covenyiAcacia covenyi
Author: Fir0002 (GFDL)

Acacia constrictaAcacia constricta
Author: Stan Shebs (GFDL)

Acacia farnesianaAcacia farnesiana
Author: United States Geological Survey (public domain)

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