Cape honey flower
Melianthaceae (honey flower)
Also known as
False castor oil plant, castor oil plant (misnamed)
Where is it originally from?
What does it look like?
Smelly, clump-forming shrub (<2+ m), with stout, rough, soft-wooded, hollow stems and suckering root system. Frond-like leaves (50-100 cm long), are covered in grey, hairy down especially underneath, are divided into 11-21 distinctively folded leaflets (8-15 cm long) and are deeply serrated with 1 cm teeth along edges. Tall, erect flower stalk (40-80 cm) has foul smelling, dark reddish-brown flowers (2 cm long, Jul-Apr) which produce large amounts of nectar, are followed by inflated, papery, sharply-angled seed capsules (2-5 cm long) containing long, shiny black seeds (5-6 mm long).
Why is it weedy?
Seed are long-lived and it forms dense, spreading stands via suckering roots. Grows in well drained soils of any quality, tolerates wind, salt, hot and cold temperatures, and damp or drought conditions and is partly shade-tolerant. Poisonous (not grazed).
How does it spread?
Seed capsules are water-borne (sea or fresh) and to a lesser extent, wind-borne. Suckering roots are spread in dumped vegetation. Common sources are gardens, waste places, and tips.
What damage does it do?
Smothers low-growing coastal species, forming large stands and destroying habitats, often leading to subsequent invasion by weedy vines. Native birds may be affected by nectar.
Which habitats is it likely to invade?
Sand dunes, sheltered coastal and steep areas, estuaries, inshore islands, disturbed lowland forest margins, shrubland, and fernland, especially on the east coast
What can I do to get rid of it?
1. Dig out small plants (all year round). Dispose of roots at a refuse transfer station, or burn or bury them deeply.
2. Cut down and paint stump (all year round): metsulfuron-methyl 600g/kg (5g/L) or a product containing 100g picloram+300g triclopyr/L (200ml/L). Follow up on suckering shoots continuously.
3. Spray large sites (spring-summer): metsulfuron-methyl 600g/kg (5g/10L) or a product containing 100g picloram+300g triclopyr/L (25ml/10L). Add penetrant. Follow up regularly to check for root regrowth.
What can I do to stop it coming back?
Roots resprout profusely. Livestock won't eat it because of taste and poison, however they will eat wilting leaves. Plant invades grazed sites, therefore exclude livestock at all times, especially when controlling weed. Cut stems may be left on site to rot down, however followup on root regrowth will be needed.