Pacific Island Ecosystems at Risk (PIER)
Hedychium gardnerianum
RISK ASSESSMENT RESULTS: High risk, score: 16
|
Australian/New Zealand Weed Risk Assessment adapted for Hawai‘i. Research directed by C. Daehler (UH Botany) with funding from the Kaulunani Urban Forestry Program and US Forest Service Information on
Risk Assessments |
Hedychium gardnerianum Sheppard ex Ker Gawl.; kahili ginger, ginger lily |
Answer |
||
1.01 |
Is the species highly domesticated? |
y=-3, n=0 |
n |
1.02 |
Has the species become naturalized where grown? |
y=-1, n=-1 |
y |
1.03 |
Does the species have weedy races? |
y=-1, n=-1 |
n |
2.01 |
Species suited to tropical or subtropical climate(s) (0-low; 1-intermediate; 2-high) – If island is primarily wet habitat, then substitute “wet tropical” for “tropical or subtropical” |
See Append 2 |
2 |
2.02 |
Quality of climate match data (0-low; 1-intermediate; 2-high) see appendix 2 |
2 |
|
2.03 |
Broad climate suitability (environmental versatility) |
y=1, n=0 |
y |
2.04 |
Native or naturalized in regions with tropical or subtropical climates |
y=1, n=0 |
y |
2.05 |
Does the species have a history of repeated introductions outside its natural range? y=-2 |
?=-1, n=0 |
y |
3.01 |
Naturalized beyond native range y = 1*multiplier (see Append 2), n= question 2.05 |
y |
|
3.02 |
Garden/amenity/disturbance weed y = 1*multiplier (see Append 2) |
n=0 |
|
3.03 |
Agricultural/forestry/horticultural weed y = 2*multiplier (see Append 2) |
n=0 |
n |
3.04 |
Environmental weed y = 2*multiplier (see Append 2) |
n=0 |
y |
3.05 |
Congeneric weed y = 1*multiplier (see Append 2) |
n=0 |
y |
4.01 |
Produces spines, thorns or burrs |
y=1, n=0 |
n |
4.02 |
Allelopathic |
y=1, n=0 |
n |
4.03 |
Parasitic |
y=1, n=0 |
n |
4.04 |
Unpalatable to grazing animals |
y=1, n=-1 |
|
4.05 |
Toxic to animals |
y=1, n=0 |
n |
4.06 |
Host for recognized pests and pathogens |
y=1, n=0 |
n |
4.07 |
Causes allergies or is otherwise toxic to humans |
y=1, n=0 |
n |
4.08 |
Creates a fire hazard in natural ecosystems |
y=1, n=0 |
n |
4.09 |
Is a shade tolerant plant at some stage of its life cycle |
y=1, n=0 |
y |
4.1 |
Tolerates a wide range of soil conditions (or limestone conditions if not a volcanic island) |
y=1, n=0 |
y |
4.11 |
Climbing or smothering growth habit |
y=1, n=0 |
n |
4.12 |
Forms dense thickets |
y=1, n=0 |
y |
5.01 |
Aquatic |
y=5, n=0 |
n |
5.02 |
Grass |
y=1, n=0 |
n |
5.03 |
Nitrogen fixing woody plant |
y=1, n=0 |
n |
5.04 |
Geophyte (herbaceous with underground storage organs -- bulbs, corms, or tubers) |
y=1, n=0 |
y |
6.01 |
Evidence of substantial reproductive failure in native habitat |
y=1, n=0 |
n |
6.02 |
Produces viable seed. |
y=1, n=-1 |
y |
6.03 |
Hybridizes naturally |
y=1, n=-1 |
y |
6.04 |
Self-compatible or apomictic |
y=1, n=-1 |
|
6.05 |
Requires specialist pollinators |
y=-1, n=0 |
y |
6.06 |
Reproduction by vegetative fragmentation |
y=1, n=-1 |
y |
6.07 |
Minimum generative time (years) 1 year = 1, 2 or 3 years = 0, 4+ years = -1 |
See left |
2 |
7.01 |
Propagules likely to be dispersed unintentionally (plants growing in heavily trafficked areas) |
y=1, n=-1 |
y |
7.02 |
Propagules dispersed intentionally by people |
y=1, n=-1 |
y |
7.03 |
Propagules likely to disperse as a produce contaminant |
y=1, n=-1 |
n |
7.04 |
Propagules adapted to wind dispersal |
y=1, n=-1 |
n |
7.05 |
Propagules water dispersed |
y=1, n=-1 |
y |
7.06 |
Propagules bird dispersed |
y=1, n=-1 |
y |
7.07 |
Propagules dispersed by other animals (externally) |
y=1, n=-1 |
n |
7.08 |
Propagules survive passage through the gut |
y=1, n=-1 |
y |
8.01 |
Prolific seed production (>1000/m2) |
y=1, n=-1 |
n |
8.02 |
Evidence that a persistent propagule bank is formed (>1 yr) |
y=1, n=-1 |
|
8.03 |
Well controlled by herbicides |
y=-1, n=1 |
y |
8.04 |
Tolerates, or benefits from, mutilation, cultivation, or fire |
y=1, n=-1 |
y |
8.05 |
Effective natural enemies present locally (e.g. introduced biocontrol agents) |
y=-1, n=1 |
y |
Total score: |
16 |
Supporting data:
Notes |
Source |
|
1.01 |
no evidence |
|
1.02 |
(1) New Zealand, (2) Réuniond, (3) Hawaii, (4) Azore |
(1) Byrne, J. (1992) Wild ginger [Hedychium gardnerianum]:
aggressive invader of New Zealand's native forests. Horticulture in New
Zealand, 1992, Vol. 3, No. 2, pp. 10-14, 15 ref. |
1.03 |
"H. gardnerianum var. pallidum. This quick growing form has the same wonderful scent but the inflorescence is shorter and broader and the flowers are a paler, primrose yellow than in typical H. gardnerianum. " [no evidence showing this variety is weedy] |
http://www.kobakoba.co.uk/hedychium_gardnerianum.htm |
2.01 |
Distributional range: |
USDA, ARS, National Genetic Resources Program. |
2.02 |
||
2.03 |
(1) Hardiness: 8-11 (2) The plant grows in wet habitats between sea level and 1,700 m (3)it can adapt to various Azorean habitats |
(1) http://plantsdatabase.com/go/952/index.html (2) http://www.hear.org/pier/species/hedychium_gardnerianum.htm (3)http://www.azores.com/history/Background.asp |
2.04 |
Distributional range: |
USDA, ARS, National Genetic Resources Program. |
2.05 |
widely cultivated in tropics |
USDA, ARS, National Genetic Resources Program. |
3.01 |
(1) New Zealand, (2) Réuniond, (3) Hawaii, (4) Azore |
(1) Byrne, J. (1992) Wild ginger [Hedychium gardnerianum]:
aggressive invader of New Zealand's native forests. Horticulture in New
Zealand, 1992, Vol. 3, No. 2, pp. 10-14, 15 ref. |
3.02 |
"Infestation sites include domestic gardens" [it is planted in gardens; not clear if it is a weed within gardens] |
http://www.ebop.govt.nz/weeds/weed52.asp |
3.03 |
no evidence |
|
3.04 |
considered as an invasive species in (1) New Zealand, (2) Réuniond, (3) Hawaii, (4) Azore (5)Both species of Hedychium threaten Clermontia samuelii (A.C. Medeiros, pers. comm. 1995), and H. gardnerianum is a threat to Labordia tinifolia var. lanaiensis (R. Hobdy, pers. comm. 1994). (6)displacing all other plants..There are major infestations at Koke'e, Kaua'i; Nahiku, Maui; and Volcano, Hawai'i. |
(1) Byrne, J. (1992) Wild ginger [Hedychium gardnerianum]:
aggressive invader of New Zealand's native forests. Horticulture in New
Zealand, 1992, Vol. 3, No. 2, pp. 10-14, 15 ref. |
3.05 |
yellow ginger (Hedychium flavescens) is also considered a pest in New Zealand |
http://www.ebop.govt.nz/land/media/pdf/pp0298.pdf |
4.01 |
no description of these traits |
http://www.hear.org/pier/species/hedychium_gardnerianum.htm |
4.02 |
no evidence |
|
4.03 |
no evidence |
|
4.04 |
no evidence |
|
4.05 |
no evidence |
|
4.06 |
no evidence |
|
4.07 |
no evidence |
|
4.08 |
"Forests, regenerating forest, streamside and alluvial forests, forest light gaps and gullies. Stable habitats except for very dry or rocky areas." [unlikely, habitat wet environment, with high water content plant tissue] |
http://www.ebop.govt.nz/weeds/weed52.asp |
4.09 |
"The wild ginger species prefer to grow in open, lightfilled environments which are warm and moist, but will readily grow in semi and full shade beneath the forest canopy." |
http://www.ebop.govt.nz/land/media/pdf/pp0298.pdf |
4.1 |
"Forests, regenerating forest, streamside and alluvial forests, forest light gaps and gullies. Stable habitats except for very dry or rocky areas. It is often seen along river flats and lower valley flats" [wide environment adaptability, limited by moisture only] |
|
4.11 |
"Coarse herbs with leafy shoots 1-2 m tall." |
http://www.hear.org/pier/species/hedychium_gardnerianum.htm |
4.12 |
"can form dense colonies in native forests, smothering young native plants as well as preventing native seedling establishment. This leads to the alteration of both the function and structure of native forest and in some instances results in the total death of the forest." |
http://www.ebop.govt.nz/land/media/pdf/pp0298.pdf |
5.01 |
"Forests, regenerating forest, streamside and alluvial forests, forest light gaps and gullies. Stable habitats except for very dry or rocky areas." [unlikely, nhabitat wet environment, with high water content plant tissue] |
http://www.ebop.govt.nz/weeds/weed52.asp |
5.02 |
Coarse herbs with leafy shoots 1-2 m tall. Zingiberaceae |
http://www.hear.org/pier/species/hedychium_gardnerianum.htm |
5.03 |
Zingiberaceae |
|
5.04 |
"Wild ginger grows from large, branching rhizomes (tuberous roots). These rhizomes, up to 3.5 cm in diameter and 10 cm in length, produce vertical stems annually. Beds of living rhizomes can form a dense layer up to a metre thick." |
http://www.ebop.govt.nz/land/media/pdf/pp0298.pdf |
6.01 |
invade native forest |
Byrne, J. (1992) Wild ginger [Hedychium gardnerianum]: aggressive invader of New Zealand's native forests. Horticulture in New Zealand, 1992, Vol. 3, No. 2, pp. 10-14, 15 ref. |
6.02 |
"Kahili ginger is also spread by birds, such as blackbirds, eating and dispersing seeds away from the original infestations." |
http://www.ebop.govt.nz/land/media/pdf/pp0298.pdf |
6.03 |
"For example, Brian Mathew originally identified Tony Schilling's wild collected 'Tara' as a form of Hedychium coccineum in which species it has remained since 1972. Recently, Hedychium specialist Tom Wood has detected elements of Hedychium gardnerianum in 'Tara' to such an extent that he has proposed it be transferred to that species. Hedychium coccineum and H. gardnerianum do occur together in Nepal and 'Tara' may be a natural hybrid. " |
http://www.kobakoba.co.uk/hedychium.htm#Hedychium%20hybrids |
6.04 |
no evidence |
|
6.05 |
(1)based on chracters of the flower, this species may be pollinated by moth as yellow ginger (Hedychium flavescens) (2)unusual long stamens [seems to require a specialized moth for efficient pollen transfer] |
(1)http://www.botany.hawaii.edu/faculty/carr/zingiber.htm (2)http://www.cannaluver.com/HedychiumGardnerianumKahiliGinger.html?1016341918710 |
6.06 |
"Propagation: By stolons where already established." |
http://www.hear.org/pier/species/hedychium_gardnerianum.htm |
6.07 |
rapid growing herbaceous perennial [minimum estimate] |
http://www.arcadian-archives.com/gingerlilies.htm |
7.01 |
"The major source of this spread is by the illegal dumping of wild ginger rhizomes on roadsides or in bush." |
http://www.ebop.govt.nz/land/media/pdf/pp0298.pdf |
7.02 |
widely cultivated in tropics |
USDA, ARS, National Genetic Resources Program. |
7.03 |
no evidence |
|
7.04 |
Red seeds (1.5 to 1.8 cm long) are produced by Kahili ginger. [large seed dispersed by birds] |
http://www.ebop.govt.nz/land/media/pdf/pp0298.pdf |
7.05 |
"Forests, regenerating forest, streamside and alluvial forests, forest light gaps and gullies. It is often seen along river flats and lower valley flats. "; "Also dispersed by water and soil disturbance." |
http://www.ebop.govt.nz/weeds/weed52.asp |
7.06 |
Conspicuous, fleshy, red seeds are dispersed by frugivorous birds |
http://www.hear.org/pier/species/hedychium_gardnerianum.htm |
7.07 |
no known means of attachment |
|
7.08 |
bird-dispersed |
|
8.01 |
(1)"Red seeds (1.5 to 1.8 cm long) are produced by Kahili ginger during the autumn and winter months, with over 100 seeds per flowerhead being produced under full-light conditions. Seed production tends to decrease as light levels decline under the forest canopy." [probabaly not, need about 10 flowering stalk to reach 1000 seeds per square meter in optimal condition] (2)The plant does not produce seeds in large numbers |
(1)http://www.ebop.govt.nz/land/media/pdf/pp0298.pdf (2)Weber, E. 2003. Invasive plant species of the world. CABI Publishing. Cambridge. |
8.02 |
"Wild ginger grows from large, branching rhizomes (tuberous roots). These rhizomes, up to 3.5 cm in diameter and 10 cm in length, produce vertical stems annually. Beds of living rhizomes can form a dense layer up to a metre thick." [no evidence regarding soil seed bank but its rhizomes could be persistent] |
http://www.ebop.govt.nz/land/media/pdf/pp0298.pdf |
8.03 |
"Chemical Control: The common herbicides that are suitable include Escort, Roundup and Amitrole. Use the 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." |
http://www.doc.govt.nz/Conservation/003~Weeds/Wild-Ginger.asp |
8.04 |
(1)"The major source of this spread is by the illegal dumping of wild ginger rhizomes on roadsides or in bush."; "Also dispersed by water and soil disturbance." (2)cut it down and it can quickly recover |
(1) http://www.ebop.govt.nz/land/media/pdf/pp0298.pdf (2) http://www.ebop.govt.nz/weeds/weed52.asp (2)http://www.azores.com/history/Background.asp |
8.05 |
a pathogenic bacterium(Ralstonia solanacearum) was found in Hawaii and tested for biological control |
Anderson, R. C. Gardner, D. E. (1999) An evaluation of the wilt-causing bacterium Ralstonia solanacearum as a potential biological control agent for the alien kahili ginger (Hedychium gardnerianum) in Hawaiian forests. Biological Control, 1999, Vol. 15, No. 2, pp. 89-96, 27 ref. |
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This page updated 8 February 2005