What are weeds? Weed search A-Z Weed list Banned plants

Back to search results
Search again
   
PDF Brochure

 


Detailed information sheet

Click on the photos for a larger image.


Botanical name :
Hedychium gardnerianum
Family :
Zingiberaceae (ginger) family 
Common name :
wild ginger, kahili ginger
Also known as :
kahili ginger, ginger lily     
Where is it originally
from? :
South Africa
What does it look like? :
Non-woody perennial to 2 m tall, ginger-scented. Massive, taro-like rhizomes are long, shallow rooted, much-branched, growing over each other close to the ground surface, and form deep beds. Each rhizome segment (4 x 10 cm) usually produces an aerial stem annually. Soft, erect stems (to 2 m) are unbranched and thicken to a short pinkish ‘collar’ at the base. Shiny, slightly hanging leaves (20-45 x 10-15 cm) are alternate. Flowerheads (25-45 cm tall) with many fragrant, lemon-yellow flowers with conspicuous red stamens are produced from January to March and develop into a fruiting spikes with fleshy orange fruits (15-20 mm long) containing many bright scarlet seeds. 
Are there any similar
species? :
H. flavescens, Canna species, and Zingiber spectabile are similar. Alternatives: A couple of nice natives you could try instead are Parataniwha (Elatosterma rugosum) or Rengarenga lily (Arthopodium cirratum).
Why is it weedy? :
Extremely shade-tolerant, tolerates most soil types, good or poor drainage and fertility, and is drought and frost tolerant once established. Long-lived, fast growing and forms deep rhizome beds. 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.  Wild ginger can grow within native bush. Nothing can grow up through the mats of tubers, and the dense leaves block light and smother natives.
How does it spread? :
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.  
What damage does it do? :
Dense rhizome beds replace all other species, and are shallow rooted, so when they become heavy with rain they can slip on steep sites and streambanks, causing erosion. Succeeded only by weedy vines. 
Which habitats is
it likely to invade? :
Most habitats except dry rocky areas: damp forest and margins, streamsides, river systems, shrublands, fernland, and inshore islands. It is frost-tender but grows under canopy in cool forests. 
What can I do to get
rid of it? :
Plants in deep shade produce few or no seed, so begin control on margins to minimise reseeding. 
1. Cut down and paint stump (all year round): cut above pink ‘collar’ at base and apply or glyphosate (250ml/L) or metsulfuron-methyl 600g/kg (1g /L). Leave stems and leaves on site to rot down. 
2. Dig or pull out small plants (all year round). Don’t compost, leave on site to rot down or hang rhizomes in trees, as they survive indefinitely. Dispose of rhizomes at a refuse transfer station or by drying out and burning.
3. Spray (all year round): metsulfuron-methyl 600g/kg (5g/10L knapsack). Add penetrant in winter. For dense patches keep spray away from roots of vulnerable plants.  Don’t replant sprayed sites for 6 months.
What can I do to
stop it coming back? :
Seeds survive for 2-4 years so it is possible to eliminate this plant from sites. Maintain rolling front and check for seedlings annually. 

Description:Hedychium gardnerianum, wild ginger, close up of fruit, Kilbirnie, Wellington.Photo:by C.Howell.

Description:Hedychium gardnerianum, wild ginger, Waipoua River, Kauri Coast Area, Northland, February 1999.Photo:by T.McLuggage.

Description:Hedychium gardnerianum, wild ginger, Whangaroa, Northland, close up of flower.Photo:S.Timmins.

Photo:  wild ginger / kahili ginger seedheads  Photo by: Weedbusters

 

For more detailed botanical descriptions of weed species, check out the Plant Conservation Network's website at http://www.nzpcn.org.nz/exotic_plant_life_and_weeds/index.asp

Click here for Herbicides and Trade names

*The chemical control methods in this manual were devised by Department of Conservation staff for Department of Conservation operations and should not be used as a substitute for the pesticide manufacturer's label instructions. The Department of Conservation takes no responsibility for any liability or damage to any person, property or thing which may occur as a result of the use of any pesticide in accordance with the chemical control methods contained on this website.

 

Back to search results