Kangaroo acacia
Botanical name
Acacia paradoxa
Family
Fabaceae (pea)
Also known as
Acacia armata, Racosperma paradoxum
Where is it originally from?
Australia
What does it look like?
Shrub or small tree (<3 m tall) with furrowed twigs that are moderately hairy. Leaves (10-18 x 2-8 mm) reduced to small, oval, asymmetric flaps on stem and thin stiff spines at base. Clusters of 5+ small, golden, pea-sized flowers (Jul-Oct) are followed by hairy, straight or curved seed pods (40-50 x 3-4 mm).
Are there any similar species?
Prickly Moses (A. verticillatum) has thinner ‘leaves’, pale yellow flowers.
Why is it weedy?
Produces many, long-lived seeds. Tolerates dry to damp, poor soils (fixes own nitrogen), little shade, wind, damage (thorny, not grazed), and high to moderately cool temperature. Grows rapidly and forms dense thickets.
How does it spread?
Seeds are spread by soil, and occasionally water, movement, from waste places, old hedges, roadsides, quarries.
What damage does it do?
Forms tall, dense, impenetrable stands in disturbed and bare sites, preventing native species establishing. Fixes nitrogen so may affect ability of specialised low-fertility native plant communities (ferns, orchids, kauri, etc) to grow.
Which habitats is it likely to invade?
Open and disturbed shrubland, short tussockland and bare land, especially in warmer areas.
What can I do to get rid of it?
1. Physical removal - Hand pull small plants, or dig out entire plant including roots (all year round)
2. Cut and paste (all year round) - Cut the stem/trunk as close to the ground as possible and cover the entire stump with herbicide as soon as possible after cutting. Apply either metsulfuron gel (10g/l strength) OR picloram gel (43g/l strength) to the entire cut stem. When a gel is inadequate apply a solution of diesel and product containing triclopyr + picloram (20:1 diesel:triclopyr/picloram). Apply the mixture over the entire exposed surface of the cut stump, i.e. top and sides.
3. Basal spray - stems up to 20cm diametre with X-Tree Basal. Apply from the ground to a height of 6 times the diameter of the plant, ensure the base is thoroughly covered at ground level.
4. Foliar spray (plants up to 1.5m) - 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?
Can be succeeded in tall canopy habitats by taller native species (not in kauri or tanekaha forest). These sites can be left, regeneration can be speeded by slashing, selective spraying or replanting of shade-creating species. Clear roads, quarries. Maintain pest and livestock control, as plant is not readily grazed.
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