ORIGIN

India, Himalayan Region

COMMON NAME

Kahili ginger

BOTANICAL NAME

Hedychium gardnerianum

IDENTIFICATION

Herb with stems to 2 m. Leaves oblong-lanceolate (lance-shaped), off stems or basal stock (emerging from the ground directly). Large rhizome. Flowers in terminal spikes, fragrant. Note the presence of red stamens in the flowers of Kahili ginger. These are not present in the more cream coloured flowers of yellow ginger. Kahili ginger is also a larger plant, with larger leaves. Plant grows 2-3 m high. Flowers Jan-Mar.

HABITATS

Forests, regenerating forest, streamside and alluvial forests, forest light gaps and gullies. Stable habitats except for very dry or rocky areas. Growth is suppressed in very dark areas of forest. It is often seen along river flats and lower valley flats.

IMPACT TO BIOTA AND ECOSYSTEMS

Forms vast colonies. Permanent smothering of stream ecosystems and forest ground tier, preventing regeneration almost entirely. Once fully established it is extremely difficult for native seedlings to regenerate. May permanently displace rare plants or cause serious losses to populations of uncommon plants or specialised communities.

DISPERSAL ROUTES, VECTORS, INFESTATION SOURCES

Seed dispersed by birds. Also dispersed by water and soil disturbance. Infestation sites include domestic gardens, dumping sites of garden waste. Bulking up areas commonly along forest edges, pine plantations, road edges, streams and unfarmed land.

MANAGEMENT

Physical Control
Slash stems and dig out all rhizomes and tubers. Pull out young seedlings (NB old shade suppressed plants may appear small but have a string of rhizomes attached to them).

Disposal
Stems and leaves may be left to mulch. Do not mulch or compost rhizomes because they always resprout. Bury rhizomes at a landfill, or dry and thoroughly burn.

Chemical Control
Spray foliage or slash stems and spray cut stumps.

Metsulfuron + Penetrant. Apply from spring to late autumn.

Rate - Handgun 25 g Metsulfuron + 100 mls Penetrant/100 litres water. Knapsack 5 g Metsulfuron + 10 mls Penetrant/10 litres water.

Biological Control

Recommended Approach
Systematically eradicate plants from site. Kahili ginger spreads relatively slowly so systematic eradication can be possible over quite large areas.

FURTHER COMMENT

For further information please refer to Environment Bay of Plenty's Fact Sheet PP02-Wild Ginger

This plant is prohibited from propagation, sale and distribution within New Zealand!