Kangaroo Island
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African boxthorn (Lycium ferocissimum)

African boxthorn (Lycium ferocissimum)

Very High Risk Weed for Kangaroo Island

African boxthorn 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

African Boxthorn was originally introduced to Australia from South Africa in the Mid 1800’s and today is widely distributed on the eastern end of Kangaroo Island, particularly in coastal and subcoastal areas near settlements, but isolated infestations are also found on the north coast as far west as Kangaroo Beech. Dispersal is primarily from seed which almost always spread by birds.

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

There has been a long history of controlling boxthorn on Kangaroo Island. In recent years the focus has been on protecting sites and control along roadsides. Help reduce the spread of African boxthorn by controlling plants on your property.

You can help by removing or killing any boxthorn on your property to help prevent there spread.

African boxthorn (Lycium ferocissimum)

DESCRIPTION

  • Growth form: Large, dense, thorny shrub up to 5 m high with extensive root and sucker systems.
  • Leaves: Small, bright green, narrow, often clustered along stems.
  • Flowers: Small, white to violet, trumpet-shaped, appearing late winter to summer.
  • Fruit: Orange-red berries, 6–10 mm diameter.
  • Seed: Each berry contains multiple seeds; a mature shrub can produce thousands of seeds annually. Seeds remain viable in soil for 4–5 years, allowing infestations to re-establish if not controlled.
  • Similar looking native species Christmas bush (Bursaria spinosa ssp. spinosa)

IMPACTS

Boxthorn invades native vegetation, alters habitat and overruns pastures. It forms dense impenetrable thickets that reduce access for stock, native animals, people and vehicles. Boxthorn thickets often harbour feral cats, leading to impacts for farmers due to increased prevalence of disease, e.g. toxoplasmosis, in sheep. 

Boxthorns also harbour rats and starlings which feed on boxthorn berries and thus contribute to the spread of boxthorn. Over time, boxthorn infestations can become extremely large and expensive to control.

CONTROL OPTIONS

Control can include physical and chemical methods. Small plants can be cut and swabbed with 10;1 Glyphosate or sprayed with a knapsack. Large plants must be sprayed with a handline or mechanically grubbed with heavy machinery. 

Be aware, African boxthorn is persistent and can regrow from root segments, fruits can ripen on cut branches and plants can defoliate after chemical treatment but then recover. 

It is imperative that any efforts of control are followed by ongoing monitoring and treatment

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

Learn more about KI farmers invited to join new African boxthorn national biocontrol program - ongoing support to 2028.

DECLARATIONS

African boxthorn is declared under the following sections of the Landscape South Australia Act 2019:

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

FURTHER INFORMATION

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