Kingdom: Plantae
Division: Magnoliophyta
Class: Magnoliopsida
Order: Fabales
Family: Fabaceae
Subfamily: Faboideae
Genus: Ulex
Species: U. europaeus
Binomial name Ulex europaeus
Common name: Gorse
Ulex europaeus is a major invasive plant species in New Zealand and millions of dollars are spent on its control. It is one of the most widely recognised agricultural weeds in New Zealand. It covers 700,000 hectares (1,700,000 acres) 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.
It was introduced from Western Europe in 1835. The seed was brought in by the English settlers as a cheap and effective plant for farm hedges and shelter. There were no natural biological controls and our climate suited it. Its seeds remain viable in the ground for at least 50 years. It was declared a noxious weed in 1990.
A lack of natural control agents in New Zealand in combination with high seed production, unpalatability to stock, and invasive, colonising growth habitats have allowed gorse to become the widespread problems it is are today. Because it is such a problem in some areas of New Zealand several insects have been introduced as a biological control to attack Ulex europaeus, all are native to Europe. They are:
Gorse seed weevil (Exapion ulicis) first imported in 1926 and are now abundant in most areas.
Gorse soft shoot moth (Agonopterix ulicetella) first imported in 1983
Gorse spider mites (Tetranychus lintearius) first imported in 1988
Gorse thrips (Sericothrips staphylinus) first imported in 1989
Gorse pod moth (Cydis ulicetana) first imported in 1989
Gorse colonial hard shoot moth (Pempelia genistella) first imported in 1995
Two native insects that attack gorse are Gorse stem miner (Anisoplaca ptyoptera) and Lemon tree borer (Oemona hirta).
Nowadays it is recognised that Ulex europaeus (Gorse) has some value and its benefits are worth mentioning. Where Ulex europaeus is established on the ground that was once native forest, it has been found to be a good nursery for native plant seedlings. Since Ulex europaeus is a leguminous plant it fixes nitrogen in the soil hence native seedlings are then both fertilised and sheltered. When these native species grow higher than the gorse they ultimately smother it. The flowers are a great source of pollen and nectar for bees as it is one of the first plants to flower in late winter.
Gorse on the hill at Whitareia Park, Wellington. Looking from Mana.
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Gorse seed heads November.
Gorse flowers
Aerial roots of Ulex europaeus.
Photos below of gorse with the imported Gorse spider mite (Tetranychus lintearius)
