Chrysanthemoides monilifera subsp. monilifera
Also known as
Saltbush, bitou bush (subspecies rotundata), Higgins curse, Osteospermum monilifera
Where is it originally from?
What does it look like?
Bushy, semi-woody, much branched shrub or small tree (<2-3 m) with ribbed and woolly young stems that become smooth as they mature. Smooth, leathery, bright-green leaves (70 x 35 mm) have irregularly toothed edges and are arranged alternately on the stems. Bright yellow daisy-like flowers (25-30 mm diameter) are produced from September to February and are followed by hard oval green fruit (6-9 mm) which ripen to black and each contain a hard seed.
Are there any similar species?
Other weedy subspecies exist but none are known in New Zealand. Native Olearia species, Brachyglottis kirkii are similar but none have similar fruit.
Why is it weedy?
Quickly forms dense thickets. One boneseed bush can produce 50 000 seeds every year, and each seed can remain dormant for up to 10 years. Tolerates most coastal soil types, salt, fire, wind, poor soils, and drought.
How does it spread?
Seeds are spread by birds, possums, by natural spread down cliffs below parent plants, in flotsam, occasionally soil disturbance, and possibly livestock. Common in coastal gardens in some areas.
What damage does it do?
Rapidly replaces virtually all native species under 2 m and prevents the establishment of native plant seedlings. Colonises disturbed sites faster than native species, and creates heavy shade where high light levels should occur.
Which habitats is it likely to invade?
All coastal areas, cliffs, sand dunes, estuary margins, roadsides, and inshore islands.
What can I do to get rid of it?
1. Hand pull all but the largest plants (all year round) when not in seed: Leave on site to rot down.
2. Stump swab (all year round): glyphosate (100ml/L) or metsulfuron-methyl 600g/kg (1g/L) or picloram gel or triclopyr 600 EC (100ml/L).
3. Spray: glyphosate (10ml/L + penetrant).
What can I do to stop it coming back?
Germinates freely after fire or clearance leaving bare ground. Clear from adjacent coastal gardens to remove seed sources. Follow up 6-monthly. Encourage regeneration, densely replant cleared areas where necessary.