Kangaroo Island
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Gorse (Ulex europaeus)

Gorse (Ulex europaeus)

Very High Risk Weed for Kangaroo Island

Gorse is an Alert weed for Kangaroo Island. Notify the Kangaroo Island Landscape Board. Early detection and control are the best way to prevent the next widespread weed. 

It is a declared plant for South Australia. 

THE SITUATION AND WHAT TO DO

Gorse originated in western Europe and was introduced into Australia as a hedging plant and potential fodder shrub. It was one of the first plants introduced to Australia, possibly as early as 1803 and has become one of Australia’s worst pest plants because of its invasiveness, potential for spread, and economic and environmental impacts.

Gorse is a Weed of National Significance and is a declared pest plant in South Australia under the Landscape South Australia Act 2019 

The Kangaroo Island Landscape Board has been controlling gorse for over 20 years and over 13 infestations have been found and controlled across the island. The management aims are to destroy all known plants. 

To help keep Kangaroo Island free of gorse:

Gorse (Ulex europaeus)

DESCRIPTION

  • Growth form: Dense, woody, evergreen shrub, 1–3 m high, forming thick, impenetrable thickets with spiny branches. Young stems are green and photosynthetic; older stems become woody.
  • Leaves: Seedlings have small trifoliate leaves; mature plants have rigid, sharp green spines 1–5 cm long along stems.
  • Flowers: Bright yellow, pea-shaped flowers 1–2 cm long, occurring singly or in small clusters. Flowering mainly late winter to spring. Flowers often have a coconut-like scent.
  • Fruit: Small, oval seed pods (1–2 cm) that turn dark brown to black at maturity and explode to release seeds.
  • Seed: Hard, smooth seeds 3–5 mm long; each pod contains 2–6 seeds, mature plants produce 6,000 to 10,000 seed and can remain viable in the soil for 30-50 years. 

Similar looking native plants due to their spiny, yellow-flowered appearance include the native prickly Daviesia (Daviesia ulicifolia), coastal prickly hakea (Hakea oleifolia), and some forms of Acacia that feature sharp phyllodes, though these lack the strong coconut scent of gorse.

IMPACTS

Gorse forms dense, spiny thickets that crowd out native vegetation, reduce biodiversity, and restrict access to land. 

It is highly flammable, increasing wildfire risk, and can injure livestock while reducing available pasture. Its persistent seedbank and rapid spread make infestations difficult and costly to control, impacting both the environment and agricultural productivity.

CONTROL OPTIONS

Effective control of gorse requires a combination of mechanical and chemical methods. Small infestations can be manually removed or cut, ensuring all roots and seed pods are destroyed. Herbicides can be applied to foliage or freshly cut stems to prevent regrowth. 

Control efforts should be repeated over many years, as seeds can remain viable in the soil for decades, and follow-up monitoring is essential to prevent re-establishment. Do not removed cut branches, leave on-site and burn preventing seeds from being transported across the property.

For larger infestations methods, use slashing, mulching, burning, or soil disturbance to stimulate the long-lived seedbank. 

These approaches should be combined with follow-up herbicide treatment and monitoring over many years to prevent seedlings from re-establishing.

Biological control agents are available but are not suitable for small infestation that can be destroyed.

Permitted and on-label herbicides and rates can be found on the PIRSA Weed Control Website.

DECLARATIONS

Gorse pittosporum is declared under the following sections of the Landscape South Australia Act 2019:

  • 186(1) Prohibiting entry to area
  • 186(2) Prohibiting movement on public roads
  • 188(1) Prohibiting sale of the plant
  • 188(2) Prohibiting sale of contaminated goods
  • 190 Requiring notification of presence
  • 192(1) Landowners to destroy the plant on their properties
  • 194 Recovery of control costs on adjoining road reserves

FURTHER INFORMATION

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