10 Poisonous Plants In New Zealand You Need To Be Careful Of

by Skye Macfarlane on Mar 28, 2025 0 comments

We love foraging and all things plants, but some are best admired from a safe distance. New Zealand is home to a few poisonous native plants, like ongaonga and tutu, but it's also home to many introduced poisonous species that may be growing in your backyard.

🌿Related: 5 Easy Ways To Start Wild Foraging

Around 10% of calls to our National Poisons Centre are related to toxic plants, with children accounting for 62% of these cases. While you might not be tempted to snack on the unripe berries of black nightshade, young children often explore the world through taste. Knowing which poisonous plants in New Zealand to watch out for can help keep your family safe.

1. Euphorbia

While all species of euphorbia are poisonous, particular care needs to be taken with caper spurge (Euphorbia lathyrus). Euphorbia secrete a milky sap when damaged which is highly toxic and can result in blindness if not treated quickly. There have been instances of people removing these plants by hand from their gardens and rubbing their eyes.

2. Arum lily

Originating from South Africa, this lily was introduced into Aotearoa as a garden plant. All parts of this plant are poisonous and are often involved in unintentional childhood poisonings. They are found in swampy pastures and have a large white funnel-shaped flower with a yellow spike that is visible from October through to December. The flower is then followed by orange/yellowish-green berries in the summer through to Autumn.

3. Black nightshade

Black nightshade (Solanum nigrum) is a tall plant, usually with many branches. The stems and the foliage have a purplish tinge. While not as toxic, it is often confused with deadly nightshade (Atropa belladonna) which is very rare in New Zealand. The unripe green berries of black nightshade hold the highest concentration of toxins and can cause symptoms such as vomiting, abdominal pain, diarrhea and confusion if ingested.

4. Iris

Commonly found in ornamental gardens, all parts of this beautiful plant are poisonous - but especially the roots. If ingested people can suffer from a burning sensation of the mouth, throat, abdominal pain, nausea and diarrhoea. If the seeds, leaves, sap from the leaves or the roots are touched, it can cause dermatitis.

5. Oleander

Oleander (Nerium oleander) poisoning can be fatal and can occur if the flowers, stems or leaves are ingested. It directly affects the heart, slowing heartbeats and lowering blood pressure. It also blurs vision and causes vomiting, diarrhea and stomach pain.

6. Agapanthus

Agapanthus are common plants known for their striking blue, purple, or white flowers. However, their sap can cause skin irritation, burning sensations, and rashes upon contact. If ingested, it may lead to stomach pain, diarrhea, and severe mouth ulcers. The toxic compounds found in this poisonous plant can be harmful to both humans and animals.

7. Ongaonga

Not to be confused with stinging nettle, ongaonga is a poisonous plant native to New Zealand. Our native nettle is covered in needle stinging hairs that release poison when touched. The sting is very painful and can even numb the area affected. There have been documented incidences of people and animals dying from exposure to this nettle.

ongaonga-poisonous-native-plants-new-zealand

8. Hemlock

Hemlock is a poisonous plant that can grow up to one meter and produces large white flowers. It closely resembles wild carrot, making it easy to confuse the two. However, hemlock stems are hairless with a purplish tinge, whereas wild carrot has a hairy stalk. While hemlock is primarily toxic when ingested, it can also cause skin irritation, so avoid contact.

9. Foxglove

Foxglove is a well-known poisonous plant in New Zealand, easily recognizable by its tall, striking appearance. It can grow up to two meters in height and produces clusters of tubular, bell-shaped flowers in shades of white, violet, or purple. Often found in gardens and roadsides, foxglove poses a serious risk if consumed.

All parts of the plant, including the leaves, flowers, and seeds, contain toxic compounds that can affect the heart, potentially leading to severe illness or even death. Caution is advised when handling or planting foxglove, especially around children and pets. The leaves of foxglove are often misidentified as comfrey, so always be 100% certain of identification before using anything you forage.

10. Rhus tree

The rhus tree, also known as a Japanese wax tree, is a small deciduous tree that can cause a severe allergic reaction. Every species within this genus contains urushiol, an oil that can trigger a severe allergic reaction upon contact with the skin.

While it may seem contradictory, some plants labeled as poisonous are, in fact, consumed by certain people. This is largely due to traditional knowledge, which guides when to pick, harvest, and prepare specific plant parts safely - like the karaka berry. It is also a highly specialised area of herbal medicine and practice.

Older Post

News

Recent Articles