Acacia

Family: Mimosaceae
Common Name: Wattle

The botanical name 'acacia' came from the Greek akakia meaning 'a thorn' and many of the African species are known as thorn trees. However, many species, over 750, ranging from shrubs to tall trees, are native to Australia. It is believed the common name 'wattle' originated from the Aboriginal name for the plant, wattah. Geographical descriptions have been adopted in Australia to describe certain species-Acacia baileyana is often referred to as Cootamundra wattle. Members of this family are found in several other parts of the world where they are generally known as 'mimosas'.

Wattle has been used in Australia for many purposes, both by the Aboriginals and the first settlers. The Aboriginal peoples tapped the roots of certain desert species for water, and the pioneers learned that wattle could be plastered with mud or clay to produce building materials. Wattle and daub houses were common in the early years of settlement because wattles were generally available, growing profusely in almost all areas. They grow quickly and flower early. Some are short-lived, lasting for only eight to ten years, while others live longer. Wattles in full flower are exquisite. The blossom varies in color from golden yellow, which is the most familiar, to orange and white. The flowers are either ball-shaped or bar-shaped and the foliage is extremely variable.

All species have bipinnate (feathery) leaves when young, although the leaves of many Australian species mature into a variety of different shapes. In fact, many Australian wattles do not have true 'leaves' but leaf-like parts known as phyllodes which are modified leaf stems or petioles. The seeds of the wattle have a hard waxy coat. For this reason, and because the seeds germinate through heat, they are usually the first plants to appear following a bushfire. As different species of wattle flower in different seasons, it is possible to plant a garden of wattles so that at least one is flowering at any time of the year, provided the Climate is suitable for them of course. Plant tall species for shade, low-growing species in rockeries and pots, and interesting cultivars for the color contrast of their blossoms and leaves.

Species

As it is impossible to list all species, a selection of wattles have been chosen for their horticultural merit. Not all of the following species are available outside of Australia but nevertheless there is a good representative selection available in the US, where many are grown in California and Arizona.

A. baileyana, Cootamundra wattle, is the best known of the New South Wales species. It has blueish silver leaves and clusters of golden-yellow flowers during winter and spring. It grows quickly to 5-8 m (16-26 ft) and is useful as a windbreak and for shade and shelter. New purple, red and yellow-leaved forms are being cultivated.

A. beckleri, from South Australia, is a drought-resistant shrub, with dense, leathery, gray-green foliage and large, sweetly perfumed flowers, 2 cm (1 in) in diameter, in winter. The flowers are the largest of all the species. It grows 2-4 m (6-12 ft) in height.

A. binervia grows 8-12 m (26-40 ft) tall and is ideal for coastal planting. It has grayish foliage.

A. browniana, a dense Western Australian shrub, is attractive and grows well in sandy soils to 1-2 m (3-6 ft). It has small, dark green, fern-like foliage and deep yellow globe-shaped blossoms which appear from winter to spring.

A. cardiophylla has a fine, soft, drooping foliage which makes it a favourite with gardeners. Commonly known as Wyalong wattle, it grows to a height of 2-3 m (6-10 ft), with golden blossoms from winter and spring.

A. decora, showy wattle, is a bushy wattle which grows to a height and width of 2 m (6 ft). In spring, masses of golden ball-shaped flowers appear among blueish green curved leaves. Useful in dry areas, it adapts to most soils.

A. drurnmondii, Drummond wattle, from Western Australia, has dark, ferny leaves and rod-shaped golden flowers between winter and spring. It grows to about 1.5 m (5 ft). A few good cultivars have been produced.

A. ericitblia, from Western Australia, has superb gray-green foliage and masses of beautiful bright yellow flowers at the ends of its branches from winter and spring. It reaches a height of about 1 m (3 ft), with a rather flat top, and is an attractive shrub all year round.

A. iteaphylla, Hinders Range wattle, from South Australia, grows to 3-4 m by 3-5 m (10-13 ft by 10-16 ft) and is resistant to drought and frost. It has beautiful, rather pendulous foliage, with purple new growth which complements bright yellow globe-shaped flowers that bloom in winter.

A. longifolia, Sydney golden wattle or Sally wattle, flowers in spring. A rapid-growing species to 4.5 m (14 ft), it does well in pure sand in seaside gardens. It can also be useful as a nurse tree.

A. melanoxylon, zone 8, is generally too tall for all but rural areas, growing to 30 m (100 ft) in gullies. Blackwood, as it is commonly known, is prized by cabinet-makers for its timber.

A. myrtifolia, myrtle wattle, is a small, neat wattle which grows to 2 m (6 ft). Suitable for container Cultivation, it has red-green foliage and cream flowers which bloom in winter. It does well in moist, well-drained conditions.

A. podalyriifolia, Queens-land silver wattle, is a useful, fast-growing wattle with gray foliage and beautiful, large gold ball-shaped flowers in spring. It grows to 6 m (20 ft) high.

A. pravissima, Ovens wattle, has small, triangular-shaped gray leaves, powdery yellow blooms in late winter and spring and weeping branches. It tolerates wet and cold conditions and grows to 2 m (6 ft). The prostrate form is a variety which is especially suitable as groundcover or soil-binder.

A. pubescens, downy wattle, from the central and southern tablelands of New South Wales, was one of the first Australian plants grown in early colonial gardens. It is a pretty shrub, with soft downy foliage and golden flowers in summer. It grows to 5 m (16 ft).

A. pycnantha, broad-leafed golden wattle, comes from the dry inland of Victoria and New South Wales. It makes a good sand-binder for shallow soils. Its large, perfumed golden-yellow flowers bloom in spring.

A. ulicifolia 'Brownii', Brown's wattle, is a semi-prostrate species, with sharply pointed leaves and lemon flowers in winter and spring. It reaches only 20 cm (8 in).

Cultivation

In frost-prone Climates, wattles are grown under glass, either in pots of well-drained soil-based potting compost, or in a soil border. They make fine plants for a large cool conservatory or greenhouse. Generally wattles can be easily propagated from seed at most times of the year. First pour boiling water over the seeds and allow them to stand for 12 hours. Discard any seeds that remain floating. Plant seeds in a free-draining mix, cover lightly and water in gently. It will take one to four weeks for the seeds to germinate under glass. It is interesting to watch the small, feathery leaves develop into the more mature forms. Both are sometimes visible on the seedling. Young plants should be kept moist. In frost-free Climates, they will grow in almost any type of well-drained soil, with an open aspect, provided they are protected from heavy winds. Most can endure very dry conditions. Don't grow other plants around their roots or under their branches. Trim immediately after flowering to improve bloom production and to prolong their life.