Ongaonga (Stinging Nettle) (Urtica ferox)
Adventuring in New Zealand bush is usually a fairly safe activity, aside from possible issues with weather conditions and navigation, we luckily don’t have to worry about snakes, spiders or predators. However, there are some plants that can pose dangers to human and animal health.
Ongaonga is one of the most poisonous native plants in New Zealand and is toxic to both humans and animals. Dogs can be affected as Ongaonga is often found in bushy areas which dogs enjoy running through.
Ongaonga can be found over a wide geographical area of the North and South Islands. In the Hawkes Bay an area that has been identified recently is Te Mata Park. More information on the locations within the park can be found on the Te Mata Park website and it is highly recommended to use a leash in these areas.
Identification: Ongaonga is a perennial shrub with pale green jagged leaves and fine white stinging hairs about 6mm long on branches and leaf margins. Ongaonga can grow up to 2m high.
Photos: P.B. Heenan. © Landcare Research 2014
Contact with the plant is the most common circumstance under which toxicity can occur but it is also toxic to dogs if licked or ingested.
Ongaonga symptoms vary depending on the amount of contact and can cause respiratory distress, neurological symptoms and even death. Onset of signs can be within minutes of contact.
- Difficulty breathing
- Trembling or Seizures
There are multiple possible causes of these clinical signs so it is important to contact your vet if your dog is showing the above signs. If your dog has come into known or suspected contact with Ongaonga, call your vet immediately. In the meantime, to provide some relief you can use a towel with cool water to wipe over to help remove residual plant toxins.
Emergency veterinary care and advice is available 24/7 by phoning your local Vet Services clinic.
de Lange, P.J. (2024): Urtica ferox Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/urtica-ferox/ (22/1/2024)
Manaaki Whenua – Landcare Research (2007) New Zealand Plant Names Database – Urtica ferox G.Forst. Accessed https://BiotaNZ.landcareresearch.co.nz/scientific-names/87fa824e-6904-4f50-99e1-934650dbfba6 (22/1/2024)