Location: most common in warmer areas of the North Island and in the Nelson–buller region. Distinctive features: ginger scent, large tropical leaves (50x10cm) that point upwards, often mistaken for canna lilies
Yellow ginger survives pretty much all conditions, even immersion in the sea, and spreads easily, replacing everything around them.
The plant has massive taro-like rhizomes close to the surface that are long, shallow-rooted, multi-branched, and grow over each other to form deep beds. Each rhizome segment usually produces an aerial stem each year, up to 2.5m high, which thicken to a short pinkish ‘collar’ at the base. Flowerheads (15x10cm) with cream coloured flowers overlapping in cone-like clusters are produced in May to June, but no fruit is produced.
HOW TO KILL IT
Cut down and paint stumps (all year round): cut above pink ‘collar’ at the base and apply glyphosate (250ml/l) or metsulfuron-methyl 600g/kg (1g /L). Leave stems and leaves on site to rot down.
Dig or pull out small plants (all year round). Do not compost, leave on site to rot down, or hang rhizomes in trees as they survive indefinitely. Dry them out and burn them, or dispose of them at a refuse transfer station.
Spray dense patches (away from roots of vulnerable species) all year round, use metsulfuron-methyl 600g/kg (5g/10l knapsack) napsack) and add penetrant in winter. Don’t replant sprayed sites for 6 months.