Approximately 800 species of Acacia exist; coming from a wide range of climates. You can find a wattle to suit almost any climate or situation. There are small shrubby wattles, low growing or prostrate types suitable as groundcovers or to spill over a drop, spreading bushy shrubs, upright narrow shrubs or small trees and more. Most have very attractive golden or bright yellow flowers.
Leaves either bipinnate or leaf-like structures (called phyllodes) which resemble simple leaves (but are actually expanded petioles). Flowers are usually yellow in small balls or cylinders, and prolific.
Acacias generally adapt well to low fertility soils, but very good drainage is important. Most species are fairly tolerant of dry conditions. Most are very quick growing. Seedlings may be planted out when they are about 15cm tall. Most seedlings will flower in the first or second year. Fertilise lightly with blood and bone when planting and water in. Mulch is beneficial, particularly in drier areas. Protection from grazing using tree guards may be necessary. Tip pruning after flowering helps maintain bushy growth. As a fast growing plant, it might need hard pruning if the shape becomes straggly, particularly in shadier sites. Regular light pruning may extend the lifespan of some Acacias considerably. Some species are frost sensitive when young. Most Acacia species, with the exception of a few of the taller species are short lived.
Acacias are legumes fixing nitrogen into the soil that benefits other heavy feeders. Flowers attract bees and birds. They are excellent, quick growing pioneer plants, for disturbed or degraded areas, providing protection for slower growing, or less hardy species, then usually dying or thinning out once the other species are established. Some acacia species (e.g. A. baileyana, A. longifolia) have become extensively naturalised in areas outside of their natural range, and, have the potential to become environmental weeds.
Propagated from seed treated by immersion in water that has just been boiled, and left to stand overnight or for at least 12 hours. Fertile seeds will begin to swell and may be used immediately, the others can be treated again. Seeds may also be scarified to hasten germination. Use of smoke water has had good results. Cutting are generally difficult for Acacias, although species with short phyllodes propagate fairly well from cuttings.
Pests include Borers and Gall Wasps. Diseases are rare and normally not serious, although rust galls are relatively common. Cut out and burn affected parts.
Species and Cultivars
Even though some wattles are large trees, and others small shrubs, many are small trees, suitable for small gardens. Some examples are:
Acacia acuminata (Jamwood wattle) 3-6m tall, avoid lime soils, tolerates wet soil, weeping branches, narrow leaves rich yellow flowers in late winter. Slow growing
A. aneura (Mulga) to 6-7m tall. Attractive, greyish, generally narrow phyllodes to 8cm long, and yellow rod-like flowers mainly in spring. Prefers full sun, and dry conditions.
A. baileyana (Cootamundra wattle) Highly desirable small dense tree 5-8m with silver-grey foliage and a profusion of golden yellow blooms in winter-spring. A prostrate form also exists.
Acacia baileyana prostrate
A. deanei Small tree of 5m with long racemes of pale yellow flowers in May to March.
A. fimbriata (Brisbane fringe wattle) Small bushy shrub/tree 3-6m with small pale yellow flowers. Phyllodes have a delicate fringe on their edges.
A. floribunda (White sallow wattle) Sometimes dense small tree to 6m with long phyllodes and rod-like fragrant pale yellow flowers.
A. longifolia (Sallow wattle) Very fast growing, spreading small tree to 5-8m with long bright green phyllodes and bright yellow blossoms.
A. podalyriifolia (Mount Morgan /Qld silver wattle) Quick growing highly attractive small tree to 5m with silver grey foliage and fragrant bright golden yellow blooms.
A. pycnantha (Golden wattle) Popular small pendulous tree 5-8m and highly attractive globular scented golden yellow blooms.
A. saligna (Golden wreath wattle) Fast growing small tree 6- 8m with semi-pendulant branches and slightly curved phyllodes. Globular bright golden yellow flowers in axillary racemes.
A. spectabilis (Mudgee wattle) Highly attractive small tree to 5m with stunning flowers in winter and spring. Slightly weeping habit. Needs excellent drainage.
Become an expert on the genus Acacia. ACS offers a unique course ideally suited to anyone with a passion for wattles, from the amateur gardener or naturalist to the nurseryman, farmer or professional horticulturist.
Learn about the identification and botany, and culture (planting, watering, feeding, propagation) of wattles.
as building materials, food plants, for tanning, craft, and more. Click for full course details
Study around 50 species are studied in detail.Learn about the commercial uses of Acacia