Dangerous and unwanted: Sea Spurge plants

We’ve received information from Horowhenua District Council and Department of Conservation about a weed we do not want in our dunes: Euphorbia paralias or Sea Spurge:

…a potentially serious weed threat for our coastal dunes.

DOC have confirmed that a single plant of this type has been identified at Himitangi Beach, and that care must be taken as the sap is harmful.

If sighted it needs to be reported to the MPI Biosecurity NZ Exotic Pest and Disease hotline 0800 80 99 66 as soon as possible.

The plant in Himitangi had not seeded so great that it appears to be an isolated plant not established and spreading.

Any help in keeping this from becoming established in our unique dunelands would be greatly appreciated and the more eyes we have out there looking, the better.

Please look out for this plant as you go about Waikawa Beach. If you see any don’t touch but do note its location, take a photo if possible and contact the Hotline above.

Sea Spurge plant.
Sea Spurge plant in close-up at Himitangi Beach.

Person examining Sea Spurge plant in the dunes.
Sea Spurge plant at Himitangi Beach.

Sea spurge fact sheet (720 KB PDF). (Text below)

Sea spurge

A serious threat to New Zealand’s beaches

The coastal weed sea spurge, Euphorbia paralias, was found at a beach near Aotea Harbour in the Waikato in 2012, and a single plant was detected at Mokau on the North Island’s west coast in 2019. This invasive weed would seriously impact our coastal environments if it became established. It is likely to have arrived on ocean currents from Australia.

Sea spurge infestations have caused major environmental problems at many Australian beaches by displacing native plants and changing natural patterns of sand movement.

What we are doing

Biosecurity New Zealand, the Department of Conservation, Waikato Regional Council and Taranaki Regional Council are working together on an eradication programme to stop sea spurge from establishing in those regions. The programme is focused on early detection so that plants are removed before they have time to produce seed. Activities include site management and annual survey of the coastline near Aotea Harbour.

How you can help

We need to find out if sea spurge is growing at other beaches, so let Biosecurity New Zealand know if you find any of the plants by calling the pest and disease hotline – 0800 80 99 66.

Early detection and reporting will help prevent sea spurge from establishing here.

Please don’t disturb the plants, as this could spread the seeds. Take a photo if you can and note the location as accurately as possible – GPS co-ordinates are ideal. Sea spurge has toxic sap, so be careful it doesn’t get on your skin.

What to look out for

Sea spurge is a hardy European shrub that thrives in coastal areas.

It has multiple stems that are often reddish at the base, and its spiky, tightly-packed blue/green leaves are 4–20mm long and 1–16mm wide. Green flowers bloom at the stem tips from September to May and the flower stems die off each year. The milky sap that oozes from broken stems is toxic to people and animals. The plants grow to about one metre tall in dense clusters overseas. Plants found in New Zealand were up to about 40 cm tall.

Sea spurge could establish almost anywhere along the New Zealand coastline. It looks similar to the rare native shore spurge, Euphorbia glauca, and New Zealand linen flax, Linum monogynum. However, native shore spurge has reddish flowers and much larger leaves that are 30–80mm long, while the stems of New Zealand linen flax are not reddish at the base. The New Zealand Plant Conservation Network website has photos of all these plants.

Biosecurity New Zealand exotic pest and disease line 0800 80 99 66 www.biosecurity.govt.nz

4 thoughts on “Dangerous and unwanted: Sea Spurge plants”

  1. We’ve been wondering what the strange plant is that has popped up this summer in our garden in Drake Street. Looks very much like Sea Spurge. I’ve contacted MPI about it and they are sending over an investigator. Thanks very much for the timely information.

      1. Our suspected sea spurge has been identified by MPI as not sea spurge. It is caper spurge (so many spurges, who’d have thought?). This is good and bad news. Caper spurge is not a notifiable plant (sadly it’s already established in NZ), but it is invasive and toxic and not something any of us would want to have about the place. If you do find caper spurge in your garden, MPI advice is to dispose of it carefully. Use gloves, etc, and eye protection), and make sure that the seeds are destroyed.

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