Gorse (''

Ulex europaeus ''Ulex europaeus'', the gorse, common gorse, furze or whin, is a species of flowering plant in the family Fabaceae, native to the British Isles and Western Europe. Description Growing to tall, it is an evergreen shrub. The young stems are g ...

'') was introduced to

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

in the early stages of European settlement. It is now a major

invasive plant An invasive species otherwise known as an alien is an introduced organism that becomes overpopulated and harms its new environment. Although most introduced species are neutral or beneficial with respect to other species, invasive species adv ...

species with millions of dollars spent on its control.

Introduction to New Zealand

Introduced from Western Europe in the very early stages of European settlement, it was recorded by

Charles Darwin Charles Robert Darwin ( ; 12 February 1809 – 19 April 1882) was an English naturalist, geologist, and biologist, widely known for his contributions to evolutionary biology. His proposition that all species of life have descended ...

during his voyage through New Zealand waters in 1835 as growing in hedges in the

Bay of Islands The Bay of Islands is an area on the east coast of the Far North District of the North Island of New Zealand. It is one of the most popular fishing, sailing and tourist destinations in the country, and has been renowned internationally for it ...

. Its spread and development as a weed in New Zealand's temperate climate was rapid, but settlers failed to recognise the threat; gorse seed continued to be imported and plantings deliberately established into the 1900s.

Uses

Gorse has been used for hedges and windbreaks on the

Canterbury Plains The Canterbury Plains () are an area in New Zealand centred in the Mid Canterbury, to the south of the city of Christchurch in the Canterbury region. Their northern extremes are at the foot of the Hundalee Hills in the Hurunui District, and in t ...

since the 1850s. These windbreaks have a combined length of 300,000 kilometres. Gorse at Hinewai Reserve

Gorse has been found to form a useful nursery for many species for native bush regeneration. When young, gorse bushes are very dense. As they grow older, they become 'leggy', and provide the ideal conditions for native seeds to germinate and grow. The native seedlings grow up through the gorse, cutting out its light and eventually replacing it. This technique is working successfully and within a short time frame at Hinewai Reserve on Banks Peninsula.

Problems

The introduction resulted in large spreading infestations over hundreds of hectares, peaking in the late 1940s. It was recognised as a threat as early as 1861 with the Provincial Council in Nelson passing an act to prevent the planting of gorse hedges. The seed can lie dormant on the ground for up to 50 years, germinating quickly after the adults have been removed. Unfortunately, most methods of removing adult gorse plants, such as burning or bulldozing them, create the ideal conditions for the gorse seeds to germinate and total eradication with current technology seems impossible. Gorse is now one of the most widely recognised agricultural weeds in New Zealand. It covers at varying densities — a total of 5% of the land area of New Zealand when excluding existing indigenous forest, vegetated sub-alpine and alpine areas. Gorse became New Zealand's most costly weed to control, an estimated $22 million per annum by the early 1980s.

Biological control

Current research areas are: active management of control agents, development of a bioherbicide, and the use of modelling. Biological pest control of gorse has been investigated since the 1920s. Seven different agents have been released in New Zealand. Results have been mixed, but in general neither the seed-feeding nor foliage-feeding insects are doing enough damage to be viable as a stand-alone control agent.

References

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External links