Hedychium gardnerianum and H. flavescens

Wild ginger

Also known as:

Kahili ginger, yellow ginger

Family: Zingiberaceae

Origin: South Africa

Wild Ginger clump with flowers.
Yellow ginger (pictured), also known as Kahili ginger, this is a perennial herb that grows up to 3m tall. Flowers are fragrant and large rhizomes grow underground and above the ground.
Photo credit: Jonathan Boow

Regional Pest Management Plan (RPMP) status

  • Aotea — Eradication
  • Waitākere Ranges Heritage Area priority status
  • Whole region — Sustained control
  • National Pest Plant Accord Species
  • Parkland with Significant Ecological Areas — Site-led (on-park and buffer)

View more about the RPMP statuses

General description

Perennial herbs < 3 m tall. Surface rhizomes are large and branching. Leaves are large and green. Flowers are scented, borne in spikes, yellow with red stamens in H. gardnerianum and creamy yellow in H. flavescens. Fruits are fleshy and orange.

What you need to know

To help protect our environment:

  • You must not breed, distribute, release or sell wild ginger. As wild ginger is a National Pest Plant Accord species, these restrictions apply within the Auckland region and across the whole of New Zealand.
  • You must not plant wild ginger within the Auckland region, unless you are transferring an existing plant on your land to another location within the boundaries of the same property.
  • You must destroy any wild ginger on land that you occupy if it has been planted in breach of the above rules and you are directed to do so by an authorised person.
  • If you occupy land within the buffer area of a park where wild ginger is being managed, you must destroy all wild ginger on that land. View a map of park buffers where this applies. To find out more about how we’re protecting Auckland’s parkland from pest plants, visit our pest plant buffer pages.

Auckland Council will control wild ginger at all sites within the Aotea/Great Barrier Island group where it is known to occur.

If you see wild ginger anywhere on Aotea/Great Barrier Island group, please report it to Auckland Council at pestfree@aucklandcouncil.govt.nz.

Habitats

Forest, forest and riparian margins, shrublands, fernland.

Dispersal

H. gardnerianum seed dispersed by birds. Vegetative spread from rhizome fragments. Human-mediated dispersal through dumping of garden waste.

Impact on environment

Forms dense stands, suppressing native vegetation and preventing recruitment. Potential to change forest composition. May increase erosion and alter decomposition and nutrient cycling patterns.

Control

Site Management

Follow up treated areas 3 times per year. Encourage natural regeneration of native plants or replant treated areas where possible after 2-3 treatments to establish dense ground cover and minimise reinvasion.

Recommended approaches

Physical control

Method: Cut stems and dig out rhizomes.

Plant parts requiring disposal: Seeds and rhizomes.

Disposal options: Small amounts can be rotted in a covered water barrel or remove to greenwaste or landfill.

Biocontrol

Biocontrol is currently not available for this species.

Community agrichemical control recommendations

No qualifications:

For small infestations only: Cut stump and paste freshly cut rhizomes with a small amount of metsulfuron gel.

Basic Growsafe certified: Cut stump and spray freshly cut base with 1g metsulfuron-methyl per 1 L of water. For areas of wild ginger under native forest reduce rates to 0.5g metsulfuron-methyl per 1 L of water.

Caution: When using any herbicide or pesticide please read the label thoroughly to ensure that all instructions and safety requirements are followed.

Wild Ginger growing amongst native forest.
A fast growing plant that forms large clumps. As wild ginger grows, more and more rhizomes are grown and these can stack up on each other out of the soil.
Photo credit: Jonathan Boow
Close up of Wild Ginger flowers.
Very good at producing seed, wild ginger can quickly spread through native bush. Stems and leaves are soft and can easily be cut away.
Photo credit: Jonathan Boow
Large clump of Wild Ginger showing rhizomes.
Wild ginger can grow in low light conditions, expanding through native forests with ease. As the clumps are so dense, native seeds are unable to germinate on the ground.
Photo credit: Jonathan Boow
Clump of Wild Ginger in flower in native forest.
Care must be taken when controlling ginger to remove all rhizomes as new plants can grow from fragments. Wild ginger can be dug up by hand and put into a large drum with water to drown.
Photo credit: Jonathan Boow
Wild Ginger in flower and growing with Bind Weed.
Wild ginger can survive in full sun conditions and the heat and dry. It is found in native forests, roadsides, pine forests, and anywhere that plants have been dumped.
Wild Ginger in flower and growing with Bind Weed.
Wild ginger flowers are born on long stems and are yellow with long necks. Orange anthers grow on long stems from the centre of each flower.
Wild Ginger clump with jasmine in the background.
Commonly found in areas with other weed species where soil has been disturbed and native vegetation has been removed. Wild ginger can be controlled with herbicide that must be able to penetrate into each rhizome.