Cape Honey Flower

Scientific name: Melianthus major
Other names: false castor oil plant, castor oil plant (misnamed)


About Cape Honey Flower

What does Cape Honey Flower look like?

You can't miss the Cape Honey Flower when it's growing in your yard. This smelly shrub grows up to 2+ m, with large frond-like leaves (50-10 cm long) that are covered in grey fuzz, especially underneath. The leaves are divided into 11-21 distinctive folded leaflets that are 8-15 cm long, edged with 1cm serrated teeth. The stems are stout, rough, soft-wooded and hollow leading down to a suckering root system. It flowers from July to April with tall, erect flower stalks that are 40-80 cm tall with dark reddish-brown flowers (2cm long). The flowers smell foul and produce large amounts of nectar. After flowering, inflated, papery and sharply angled seed capsules (2-5 cm long) reveal themselves, each containing long, shiny black seeds (5-6 mm long).

How does it spread?

These monsters grow well in drained soils of any quality, tolerate wind, salt, hot and cold temperatures, and damp or drought conditions, and is partly shade-tolerant. They can be found in sand dunes, sheltered coastal and steep areas, estuaries, inshore islands, disturbed lowland forest margins, shrubland, and fernland. Their suckering roots can spread in dumped vegetation, so don't be surprised to find them in gardens and waste places. 

Cape Honey Flower seeds are long living and they form dense, spreading stands via suckering roots. These seed capsules are water-borne (sea or fresh), and to a lesser extent, wind-borne. When they take root, they will smother low-growing coastal species, form large stands and destroy habitats, and lead to invasion by weedy vines. Native birds may also be affected by its nectar.

How do I get rid of it?

Small plants need to be dug out and disosed at a refuse transfer station, or burned.

Big plants need to be cut down and stumps painted with metsulfuron-methyl 600g/kg (5g/L) or Tordon Brushkiller (200mL/L). Follow-up continuously on the suckering roots. In the spring, large sites need to be sprayed with metsulfuron-methyl 600g/kg (5g/10L) or Tordon Brushkiller (25mL/10L) plus penetrant. Check regularly for root regrowth in order to be sure to be rid of this pesky weed.

What can I plant instead?

We recommmend planting some Harakeke (Phormium tenax) or the Huruhuru Whenua (Asplenium oblongifolium). What other native plant would you recommend?