What does it look like?
Both species of wild ginger are non-woody perennials, growing up to 2m tall from thick-branching rhizomes (swollen underground stems). Their dense underground root system spread up to one metre deep excluding all other species. Both species produce shiny leaves 20-45cm long.
Kahili ginger flowers January -March and produces scented, lemon-yellow flowers with conspicuous red stamens, followed by fruiting spikes with fleshy orange fruits. Yellow ginger produces scented, cream-coloured flowers in clusters, from May to June and does not produce fruit.
Both species prefer forest environments, where soils are fertile and damp, thus wild ginger has been termed a 'forest invader'. Areas where it can commonly be seen growing include forests, streamsides and alluvial forest, light gaps and gullies. It cannot tolerate very dry or rocky areas, due to the generally low fertility of the soil in such environments.
Why is it a problem?
Wild ginger can still successfully multiply when rhizomes are damaged. Young plants are very palatable to livestock, and both species tend to invade all areas where stock are excluded, including within native bush and on road sides and riverbanks. Due to it's all-smothering nature, it will eventually replaces all other species, being extremely shade tolerant, somewhat tolerant of frost and drought, and can withstand immersion in sea water.
- Cut stems and paint stumps with 1g metsulfuron-methyl (600g/kg e.g. Escort®) per 1 litre water.
- Spray 5g metsulfuron-methyl + 10ml penetrant (e.g. organosilicone) per 10 litres water.