Wild Ginger

Forest and Bird, Volume 21, Issue 3, 1 August 1990, Page 4

Wild Ginger

Anne Joyce

WO SPECIES OF GINGER have become wild in New Zealand: kahili ginger (Hedychium gardnerianum) and yellow ginger (Hedychium flavescens). Widely grown as ornamental plants, they have escaped into the wild and become a major problem. Wild ginger smothers the forest floor, forming a dense mat of roots which is virtually impenetrable. Gradually it is creeping into our native forests. It is widespread in the Waitakere Ranges, Northland and Coromandel forests. It has started to spread south and has been spotted in the wild in Wellington, near Christchurch and on the West Coast. The two species can be distinguished one from the other. Kahili ginger has a spike of lemon yellow flowers with red stamens. After flowering the seed capsules split to display red/orange seeds which are dispersed by birds, often into undisturbed forest. The

leaves are lance shaped and smooth. Yellow ginger has cream coloured flowers and its leaves are narrower. It does not set seed. Eradication Wherever possible wild ginger should be dug up, taking care to remove all the rhizomes. Do not dump the plant by the roadside or in the compost heap as the smallest rhizome will form a new plant. For large infestations, spraying is an option. The only herbicide that works is Escort. A wetting agent called Pulse can be added to the spray mixture to help the spray adhere to the leaves. Spraying should take place only from early spring to autumn. If the stems are cut, spray may be painted on each stem and on exposed rhizomes. Spraying is effective but it can take up to 18 months for the plant to die — one application only is required. ¥