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   Hedychium flavescens (herb)  français     
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      Hedychium flavescens (Photo: Gerald Carr) - Click for full size   Hedychium flavescens (Photo: Gerald Carr) - Click for full size
    Taxonomic name: Hedychium flavescens Carey ex Roscoe
    Synonyms: Hedychium emeiense Z.Y. Zhu, Hedychium panzhuum Z.Y. Zhu
    Common names: awapuhi melemele (Hawaii), cream garland lily (English), cream ginger (English), cream ginger lily (English), e mei jiang hua (Chinese-China), gingembre jaune (French-Reunion (La Réunion)), hédychie jaunâtre (French-Reunion (La Réunion)), kopi rengarenga (Cook Islands), kopi rengarenga (Cook Islands), longose jaune vanille (French-Reunion (La Réunion)), longoze (French), opuhi rea rea (French Polynesia), re'a rengarenga (Cook Islands), teuila (Samoa), wild ginger (English), yellow ginger (English), yellow ginger-lily (English)
    Organism type: herb
    Hedychium flavescens has been spread from its home-range in the Himalayas to occupy many locations around the world. It has caused great concern in countries where it has been introduced; for example in New Zealand, Hawaii and La Réunion, as it can form dense vegetative growths that may cover whole areas of land and prevent the regrowth and regeneration of native plant species. Moist warm climates in particular favour successful establishment of Hedychium flavescens.
    Description
    Coarse perennial herbs with leafy shoots 1.5-2m tall. Grows from large branching rhizomes (tuberous shoots) of up to 3.5cm in diameter. Rhizomes are internally pale and fragrant (Wagner et al., 1999, in PIER, 2002). Rhizomes grow vertical stems, grow up to 10cm long and form rhisome beds of up to a metre thick (Mather, Environment B.O.P). Leaves are oblong to lanceolate, 20-45 (-60)cm long, 5-10 (-12.5)cm wide, upper surface glabrous, lower surface sparsely pubescent, apex acuminate, sessile, ligules membranous, (1-) 2-4cm long, entire, pubescent, sheaths glabrous. Flowers fragrant, inflorescences erect, basically ovoid, 15-20cm long, ca. 8cm wide, primary bracts green, membranous along margins, loosely imbricate, broadly ovate to elliptic, 5-8cm long, ca. 3.5cm wide, apex usually obtuse, pubescent to glabrate, rachis permanently concealed, cincinni usually 4-flowered, calyx cylindrical, 4-5cm long, pubescent or rarely glabrate; corolla yellow, the tube slender, 8-9cm long, the lobes linear to linear-lanceolate, 4-5cm long; labellum often centrally flushed with dark yellow, broadly obovate, about as long as staminodes, (2.5-) 3-4cm wide, the base tapered into a claw; stamen yellow, about as long as labellum or slightly longer; lateral staminodes white, spatulate to lanceolate, (2.5-) 4-6cm long. Capsules unknown (Wagner et al., 1999, in PIER, 2002)
    Similar Species
    Hedychium gardnerianum

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    Occurs in:
    agricultural areas, natural forests, planted forests, riparian zones, ruderal/disturbed, urban areas
    Habitat description
    Yellow ginger occurs in rainforests, moist forests, along roadsides, in open habitats and along streamsides (PIER, 2002). In India it is found at altitudes of between 1200 metres and 2000 metres (KobaKoba 2001).
    General impacts
    This species is a major invader of native forests in Hawaii (Carr, University of Hawaii), New Zealand, and La Réunion (PIER, 2002). In New Zealand yellow ginger ( H. flavescens) exhibits dense rhizomal growth which aids its spread and dispersal and prevents the growth of native plants. There is concern that it may permanently displace uncommon plants or specialised plant communities in this country (NZ DOC).
    Uses
    Medicinal purposes (Brach, Flora of China).
    Notes
    Flowers produce a powerful spicy citrus scent (KobaKoba 2001).
    Geographical range
    Native range: Himalayas, Eastern india, Madagascar.
    Known introduced range: American Samoa, Cook Islands, Federated States of Micronesia, Fiji, French Polynesia, Guam, Hawai‘i, Niue, Samoa, Tonga, New Zealand, La Réunion.
    Introduction pathways to new locations
    For ornamental purposes: Cultivated in New Zealand gardens since 1865. (Mather, Environment BOP)


    Local dispersal methods
    For ornamental purposes (local): Cultivated in New Zealand gardens since 1865. (Mather, Environment BOP)
    Garden escape/garden waste: It has escaped cultivation and is now naturalised in forests and open areas (Anderson and Gardner 1999).
    Other (local): Spread outwards along the ground by way of rhizomes, with new stems sprouting annually. (Mather, Environment BOP)
    Management information
    Physical: Plants may be dug out. All seedlings must be removed to prevent regeneration. Stalks and roots are difficult to burn and should not be composted. Even small root fragments will resprout.

    Chemical: Treat with herbicide. Escort 25 gm/100 l water + 0.1% Pulse; Roundup 2% + 0.2% Pulse and Amitrole. If in doubt, use concentrations as recommended by the manufacturer. Apply from spring to late autumn. Spray lightly on the leaves and roots. Do not remove the leaves or stalks until they have gone brown and dried out. This will take three to four months. During spraying, non-target plants can be shielded with cardboard or plastic sheets. The use of a marker dye helps to avoid double spraying and wastage, and a foaming agent can be added to the spray to prevent drift.
    For larger plants, the cut stump method can be used. Cut the base of the plant close to the ground with a straight flat cut. The cut must be horizontal so the herbicide will stay on the cut area and be absorbed. Apply the herbicide as instructed on the label to the stems and roots. Apply immediately, as the sap ceases to flow once the tissues are severed. There are several convenient ways the application can be made, with a paintbrush, eye dropper or a small squeeze bottle. This method uses less spray and reduces the risk to non-target plants. Make sure you leave the plants in the ground until the roots have died off.
    Another approach is to cut and remove all stalks and leaves and rake away ground litter to expose the roots. The roots should then be sprayed, covered with leaves, and left. Don't use this method after the flowering heads have formed seeds. The spray will have noticeable effects in three months, but the plant will take 12 to 15 months to fully die and rot. With all spraying make sure to read the instructions on the manufacturer's label closely and always wear protective clothing (NZ Department Of Conservation).

    Reproduction
    Spreads outwards along the ground by way of rhizomes, with new stems sprouting annually (Environment B.O.P).
    Compiled by: IUCN/SSC Invasive Species Specialist Group (ISSG)
    Last Modified: Monday, 24 July 2006


ISSG Landcare Research NBII IUCN University of Auckland