Sea spurge

What is sea spurge?

Sea spurge is a small leafy shrub, pale green in colour. It grows to about 70 centimetres in height and has multiple stems covered in small tightly packed leaves. Small green flowers appear at the end of the stems and bloom between September and May.

Sea spurge (Euphorbia paralias) is an invasive weed native to Europe. It is thought to have been introduced to Australia in ships' ballast water about 70 years ago.

Sea spurge is found throughout southern Australia, including Victoria, Tasmania and islands of Bass Strait. In the past 20 years, it has colonised beaches along the New South Wales South Coast. However, containment efforts are underway.

Why is sea spurge a problem?

Mature sea spurge plants can produce between 5,000 and 20,000 salt-tolerant seeds per year. Seeds can survive for a number of years on ocean currents that spread them from beach to beach.

Once established, a sea spurge colony can spread rapidly, displacing the native vegetation and changing the structure of the beach. This can disrupt many native species including the endangered shorebirds such as the hooded plovers, little terns and oystercatchers that use open sand spits for nesting.

Sea spurge can grow anywhere on the beach front, from the high-water mark to well into the dunes. It colonises both bare sand and the native dune vegetation. Sea spurge has also been found on rocky foreshores and rock shelves, on the steep back dunes and inside the mouths of coastal lakes and estuaries.

Infestations of sea spurge have caused major environmental problems in Tasmania and Victoria. It is gradually working its way north and the South Coast beaches are the most threatened in New South Wales.

At present sea spurge is generally in low densities on most beaches south of Nowra. Significant effort by volunteers and government agencies has taken place on all southern NSW beaches. However, an established seed bank and re-infestation makes this an ongoing project.

Managing sea spurge – how you can help

Herbicides and manual weeding are the main control methods used for sea spurge and community action is the most effective control for this beach invader.

You can help manage sea spurge infestations:

• Notify authorities – let your local council or authority know wherever you find sea spurge. Take a photo to help your local weed officers confirm its identity.
• Get involved – join a local Landcare group or adopt a favourite beach and patrol it regularly.

Chemical control is for qualified operators only and will be undertaken by your local council or control authority for larger or more difficult infestations.

What we are doing – biocontrol with CSIRO

The Commonwealth Scientific and Industrial Research Organisation (CSIRO) was awarded $500,000 from the NSW Environmental Trust to release a fungal biological control agent in Tasmania, Victoria and New South Wales. The project is led by CSIRO and supported by NSW National Parks and Wildlife Service and Department of Primary Industries and Regional Development.

The large infestations of sea spurge in Victoria and Tasmania are sources of recurrent infestations in New South Wales and targeting these infestations will reduce spread and impact on the environment.