5 Poisonous Native Plants You Need To Know How To Recognise
We love foraging, and we love our native plants. While some plants hold beneficial medicinal properties, some are poisonous and must be avoided. But just because these fierce native plants are poisonous, it doesn’t mean you should ignore them.
Our native nettle, for example, might hold the key to new research in pain relief, while others we avoid now have a fascinating history of traditional use by those who learnt how to prepare them in a way that made then beneficial.
Knowing how to identify these poisonous native plants is particularly important if you are wild foraging, as ingesting them could be deadly. That’s why this list of New Zealand’s most poisonous native plants will benefit all of your wild adventures.
Our native nettle packs a real punch and you will find it throughout Aotearoa. Ongaonga or tree nettle (Urtica ferox) is endemic to New Zealand. Whether you’re out hiking or foraging, it is good to be able to recognise this plant so you can avoid being stung. It looks different to stinging nettle as it is much taller, sometimes reaching up to three metres. It has distinct leaves with jagged edges, and its white needles hold a painful toxin.
The tree nettle is one of our most poisonous native plants. It can cause serious damage to you or your animals (there have been cases of dogs and horses developing breathing issues, which can be fatal).
The following are some real-life incidents with ongaonga from the book “The Poisonous Plants in New Zealand.”
- “A group of trampers developed loss of coordination for three days after being stung.
- A typist developed tingling numbness in the hand after grasping a nettle bush, preventing her from typing for five days.
- Reports of severe headaches, blurred vision and extreme fatigue after exposure.
- A fatal poisoning was described in 1961, when a young man died of paralysis and respiratory problems several hours after walking through a patch of tree nettles.”
Despite its unpleasant and sometimes deadly side effects, this native plant is being researched to help with pain relief, particularly for Gullian-barre, due to its powerful numbing properties. You can learn more about that here.
Tutu refers to the eight Coriaria species that are poisonous native plants in New Zealand. Coriaria aborea is one of the most abundant and can be seen in areas with scrub and on forest margins.
It is a small tree with dark glossy pointed leaves arranged in pairs along the stem. It’s dark, enticing berries are one of the leading causes of human poisoning incidents as well as toxic honey, but livestock is also at risk if tutu is growing on grazing land.
Māori traditionally used tutu as a lotion to help with healing wounds. The lotion consisted of rimu bark and tawa bark with tutu leaves. The explorer George Vancouver, who stayed in Dusky Bay for three weeks in 1791 to recuperate his crew, was said to have used tutu in this way to help their health - alongside drinking spruce beer and eating fish.
© proteaceaejim | iNaturalist
Poroporo is a fleshy shrub that bears dark green thin narrow leaves and large white or purple flowers with a projecting yellow centre. This gorgeous plant is a bit tricky as some people say you can eat the berries when they change from green to orange as they lose some toxicity. But you can still run the risk of delayed symptoms such as fever, sweating, nausea and pain. We would err on the side of caution and probably not eat them.
Traditionally poroporo has had many uses such as a topical treatment to help with itchy skin or for sores, eczema, and psoriasis. The leaves were beaten or mulched and used as a poultice on sores and ulcers.
Interestingly poroporo was also used traditionally (and internally) as a contraceptive. A poroporo farm and factory was established in Aotearoa in the late 1970s for extracting the steroid hormone called solasodine - which was used as a steroid in contraceptives. Here, poroporo shrubs were grown specifically for the solasodine. Eventually, the poroporo plant farm had to shut down as it became cheaper to produce solasodine synthetically.
This tree is often associated with its large orange berries. While this outside flesh is not poisonous, the raw kernels of the berries have a toxin called karakin. If you consume the kernels, it could cause violent spasms, which could lead to paralysis.
Traditionally Māori would use the berries as a source of food (but had a lengthy method of preparation that made the berries edible). This had the effect of hydrolysing the toxin, thereby reducing its activity. Sometimes prepared kernels would be stored for winter or ground up into ‘flour’ for bread. The Māori treatment for karaka poisoning was to give a decoction of the kohekohe bark mixed with water.