Northlanders urged to report sightings of invasive plant sea spurge

The toxic weed sea spurge has been confirmed at two locations on Te Oneroa-a-Tōhe/Ninety Mile Beach. Photo / Mike Dinsdale

Northlanders are being asked to keep their eyes peeled for the invasive plant sea spurge after it was discovered in the Far North.

Northland Regional Council [NRC] said the weed has been confirmed at two locations on Te Oneroa-a-Tōhe/Ninety Mile Beach; one near Ahipara and one just north of Waipapakauri.

NRC councillor Peter-Lucas Jones said the weed (Euphorbia paralias) could have serious impacts on coastal environments.

There is currently only one other known site of sea spurge in Northland, located on the Pouto peninsula, but Jones believes there is potential for it to turn up at other sites along the west coast.

The weed is native to Europe, but it is likely to have arrived in New Zealand on ocean currents from Australia, where it has become a major weed on its southern coastline.

“It’s causing major environmental damage at many Australian beaches, displacing native plants and changing natural patterns of sand movements,” Jones said.

“It has the potential to overrun our native dune species and threaten the habitats of native birds.”

Sea spurge looks like a small shrub and typically grows up to 50cm high although it can sometimes reach up to one metre.

It has tightly packed leaves that are bluish green in colour, and the stem often has a red tinge at the base.

It has a milky sap which is toxic to people and animals and may cause temporary blindness.

Jones said an adult plant can produce between 5000 and 20,000 buoyant and salt-tolerant seeds every year and these can travel long distances on ocean currents.

To date, all plants have been removed from known locations and beach surveys to the north and south of these sites have been completed.

Sea spurge has the potential to overrun our native dune species and threaten the habitats of native birds.

Te Oneroa-a-Tōhe beach board chairwoman Lisa McNab said protecting the beach “is a responsibility we all share”.

“Our beach is more than just a stretch of sand; it’s a taonga handed down through generations.

“Whether you’re walking the shoreline, talking with your whānau, or joining our hui, your actions make a difference.”

Sea spurge is classified as an unwanted organism and the Ministry for Primary Industries (MPI) is the lead agency for sea spurge management.

Jones urged people not to disturb the plants - as the sap is toxic and seeds could be spread via clothing - but to take clear photos and note the location as accurately as possible.

People can report sightings to the MPI hotline on 0800 80 99 66.

Jenny Ling is a news reporter and features writer for the Northern Advocate. She has a special interest in covering roading, lifestyle, business, and animal welfare issues.