T.E.R:R.A.I.N - Taranaki Educational Resource: Research, Analysis and Information Network


Hedychium gardnerianum (Kahili Ginger)

Kingdom: Plantae
(Unranked): Angiosperms
(Unranked): Monocots
(Unranked): Commelinids
Order: Zingiberales
Family: Zingiberaceae
Genus: Hedychium
Species: H. gardnerianum
Binomial name: Hedychium gardnerianum
Common name: Kahili Ginger, Ginger Lily, Wild Ginger

Hedychium gardnerianum is a plant native to the Himalayas that grows to 2.4 m tall with long, bright green leaves clasping the tall stems.
Wild ginger is global invasive species and is a serious threat to native forests. It forms dense clumps in native forests, smothering young plants and preventing native seedlings from establishing. If left unchecked, wild ginger could permanently replace some of our native plants. It is known as 'wild kahili ginger' and is listed as a weed of concern on conservation land in New Zealand and Hawaii. It has been recognized as one of "The World's 100 Worst Invasive Alien Species" by the IUCN Invasive Species Specialist Group (ISSG).
 

Wild ginger grows from large, fleshy underground stems called ‘rhizomes’. Clumps of rhizomes can form huge impenetrable mats under the soil surface, up to one metre deep. These thick mats of rhizomes make it very difficult for other plants to grow.
Above ground, wild ginger has thick fleshy stems and large waxy leaves. It grows up to a height of two to three metres, forming a dense canopy that shades out smaller plants and seedlings. Ginger is extremely shade-tolerant, tolerates most soil types, good or poor drainage and fertility, and is drought and frost tolerant once established.
Dispersal: Seeds are spread by birds and possibly possums. Rhizomes spread slowly outward from clumps, and new plants are established from rhizome fragments spread in dumped vegetation and fill, and by soil movement, flooding, and contaminated machinery. Moderate amount of seed produced that are dispersed widely, and rhizomes resprout from any fragment and can survive immersion in the sea, crushing, and years away from soil.

   



A ginger invasion on farmland Northland NZ

The colourful red seed pods of Hedychium gardnerianum