Wild ginger in New Zealand from India

Kahili ginger

Don't let its good looks fool you. Wild ginger threatens to smother our native forests.
The plant was introduced to New Zealand from India in the 1890s. It rapidly spread throughout Auckland, Coromandel and Northland. The warm moist climate of the upper North Island favoured the initial spread of the plant and it is now a problem in parts of the top of the South Island, and on the West Coast.
There are two types of wild ginger:

• Kahili ginger (Hedychium gardnerianum)
  This plant grows up to two metres in height. It has a large cream flower with long red stamens, is strongly perfumed and produces up to 100 seeds per flower head. Of the two types of wild ginger this is the worst, because of its successful spreading by seed. As well, the plant roots spread outwards and sprout new plants.

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Yellow ginger

• Yelllow ginger (Hedychium flavescens)
  This variety has cream flowers in late autumn and early winter. Yellow ginger does not seed and therefore does not multiply as fast as Kahili. Make its removal a second priority.

http://www.doc.govt.nz/conservation/threats-and-impacts/weeds/common-weeds-in-new-zealand/wild-ginger/ 

http://tinaspicstory.blogspot.com.au/2012/05/weekend-flowers-45.html

http://floralfridayfoto.blogspot.co.nz/