Wild in the Waikato about nasty ginger pest plant
Predators like possums and rats can affect our bird populations and native plants. But so can pest plants like wild ginger.
That’s because wild ginger forms dense clumps, smothering young plants, preventing seedlings from growing and making it hard for birds to forage.
Wild ginger is the name given to Hedychium gardnerianum and Hedychium flavescens, or kahili and yellow ginger respectively.
It is found throughout the Waikato, including Hamilton.
Native to India and brought into New Zealand as flowering plants, both species have large waxy leaves and stems and can grow up to three metres tall.
Kahili ginger has yellow flowers with red stamens between January and March, and yellow ginger has yellow-white flowers between May and June.
Left unchecked, both species can replace rare native plants, creating a serious threat to native ecosystems. Wild ginger is also shade tolerant, helping it grow underneath the forest canopy.
Of the two species, kahili ginger is the only one that produces seeds in New Zealand, and these are dispersed by birds. However, both species are spread vigorously by large fleshy underground stems called rhizomes.
Under the Waikato Regional Pest Management Plan, all landowners are responsible for controlling wild ginger on their property.
The best means of control is either physically pulling out or digging up small infestations and disposing of roots and seed heads, or cutting larger stems near the root and pasting with Vigilant or Picloram gel.
The Waikato Regional Council also announced a spotty fungus is the latest arsenal in the toolbox to tackle a widespread pest plant.
The tradescantia yellow leaf spot fungus was released in a Hamilton Park. The fungus penetrates the leaves of the Tradescantia – also known as wandering willie – which smothers the ground, preventing native tree regeneration. The leaves eventually shrivel and die. This is only the second time it has been released in the Waikato.
-Waikato Weed Watch is supplied by Waikato Regional Council.