Sydney golden wattle
Botanical name
Acacia longifolia
Family
Fabaceae (pea)
Also known as
Racosperma longifolium
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 Physical removal - Hand pull or dig seedlings (all year round). Ensure minimum soil disturbance.
2. Cut and paste - Cut the stem as close to the ground as possible. Apply a solution of diesel and triclopyr (20:1 diesel:triclopyr) or commercial formulations (120g triclopyr/l of oil or product containing triclopyr and picloram 50ml/L water mix) over the entire exposed surface of the freshly cut stump, i.e. top and sides.
3. Basal spray stems up to 20cm diametre with X-Tree Basal. Ensure the base is thoroughly covered at ground level.
4. Drill or frill - Drill downward sloping holes around the circumference of the trunk about 8-10 cm apart, or Frill (make deep cuts into the sapwood at regular intervals around the base of the tree, taking care not to ring-bark the plant). Fill the holes with undiluted ‘neat’ glyphosate (360g/L active ingredient) or saturate the frill cuts with glyphosate (360g/L active ingredient) mixed at 250ml/L
5. Foliar spray (plants up to 1.5m high)- Apply Triclopyr herbicide (600g/L active ingredient) at 6ml/L plus organosilicone penetrant (1ml/L) to thoroughly wet all parts of plant OR apply Picloram/triclopyr herbicide (picloram 100g/l and triclopyr 300g/l active ingredient) at a rate of 6ml/L plus organosilicone penetrant (1ml/L) to thoroughly wet all parts of plant.Note: Tricolopyr and picloram herbicides are ‘grass friendly’ but overspray will kill other (desirable) broadleaf plants. Picloram has residual activity in the soil which may leach through soil and kill other plants. Do not use under and around other (desirable) broadleaf plants. Do not use over or near water bodies or wetlands and use only as directed on label.
CAUTION: When using any herbicide or pesticide, PLEASE READ THE LABEL THOROUGHLY to ensure that all instructions and directions for the purchase, use and storage of the product, are followed and adhered to.
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.
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