Erect, spiny, much-branched perennial shrub <2m tall. Green-brown spiny stems & branchlets, woody when mature. Bright yellow pea-like flowers (May-Nov), black seed pods explode in summer.
Open areas, riverbeds, pasture, scrubland, forest margins. Widespread throughout NZ.
Seeds spread locally <8m away after ejection from pods, also spread by birds & in gravel & soil.
Rapidly forms dense impenetrable infestations that compete vigorously with native regrowth, reduce pasture productivity, harbour pests (eg rabbits & possums), & are a fire hazard. Recovers quickly after burning & if left long enough, will act as nursery crop for native seedlings; though as a nitrogen fixer changes soil composition, affecting the type of native bush that will grow there.
When spraying, ensure total coverage to the point of running off both leaves & stems. Do not burn or graze. Only use glyphosate spray when all vegetation on site is to be removed for replanting (generally not required). Sites with appropriate tall forest spp. present can usually be left to be overtopped; can speed by selective slashing, stump swabbing or planting. Check road gravel & fill.
1. Introduce biocontrol agents wherever possible.
2. Hand pull seedlings and small plants.
3. Cut & stump paint (50ml triclopyr/1L or 1g metsulfuron/1L or 50ml Tordon BK/1L or Vigilant gel or 200ml glyphosate + 10ml penetrant/1L).
4. Spray all year round (100ml glyphosate + 20ml penetrant/10L).
5. Spray spring-summer (60ml triclopyr +10ml penetrant/10L).
6. Spray autumn-winter (5g metsulfuron+10ml penetrant/10L).
Caution: when using any herbicide or pesticide PLEASE READ THE LABEL THOROUGHLY to ensure that all instructions and safety requirements are followed.