Also known as
Acacia armata, Racosperma paradoxum
Where is it originally from?
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. Pull or dig small plants (all year round). Ensure minimum soil disturbance. Mulch.
2. Cut trunk and paint stump (all year round): cut trunk near to the ground, and swab freshly cut stump with triclopyr 600g/L (50ml/L) or metsulfuron-methyl 600g/kg (5g/L).
3. Overall spray (spring-summer): triclopyr 600g/L (60ml/10L + penetrant).
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.