Sydney golden wattle
Also known as
What does it look like?
Shrub to small tree with sharply angled, hairless or sparsely angled twigs. Alternate leaves (80-130 x 3-8 mm) are hairless, occasionally curved, and usually with 3 prominent veins. Numerous small, puffy, pale to golden yellow flowers appear in cylindrical spikes (Jul-Aug), and are followed with seeds with cup-shaped appendage.
Are there any similar species?
A. sophorae has dark reddish-brown, contorted seed pods and larger seeds, also weedy. Tasmanian blackwood (A. melanoxylon) has similar leaves, numerous flowers in round heads; large, folded seed appendages, occasionally weedy. A. pycnantha is not similar but is occasionally called Sydney golden wattle.
Why is it weedy?
Produces many, long-lived seeds, tolerates damp to drought, poor soils (fixes own nitrogen), salt, wind, damage (largely unpalatable to stock), and high to mod temperature. Grows rapidly and forms dense thickets.
How does it spread?
Seeds are spread in soil and occasionally water movement, from waste places, old hedges, roadsides.
What damage does it do?
Forms dense stands in disturbed and bare sites, and prevents native species from establishing. Fixes nitrogen, affecting specialised low-fertility plant communities (ferns, orchids, kauri, etc).
Which habitats is it likely to invade?
Shrubland, short tussockland, dry fernland, bare land, coastal areas, especially in warmer areas.
What can I do to get rid of it?
1. Pull or dig small plants (all year round): ensure minimum soil disturbance. Mulch.
2. Cut and squirt (all year round): make 1 cut every 100mm around the trunk and saturate each cut with 5ml triclopyr 600g/L (undiluted).
3. Cut trunk and paint stump (all year round): cut trunk near to the ground, and swab freshly cut stump with triclopyr 600g/L (100ml/L) or metsulfuron-methyl 600g/kg (5g/L).
4. Overall spray (spring-summer): triclopyr 600g/L (30ml/10L + penetrant).
What can I do to stop it coming back?
Dislikes growing amongst species of similar height, and is succeeded in tall canopy habitats by taller native species where their seedlings exist and have some space. These sites can be left to regenerate (20-40 years), aided by selective slashing. Do not mow site, as wattle recovers faster than native species and the higher light levels induce more seed germination. Clear all roads, quarries and other sources. Maintain native groundcover wherever possible.