Urtica ferox

Urtica ferox, commonly known as tree nettle and ongaonga, is a species of nettle endemic to New Zealand. A member of the Urticaceae, U. ferox is covered in spines or trichomes, which contain numerous toxins that are poisonous to humans. U. ferox is a large woody shrub that can grow to a height of 3 metres (10 feet), with the base of the stem reaching 12 cm (5 in) in thickness. Its large spines can result in a painful sting that can last several days or weeks, and even has resulted in one recorded human death. U. ferox is found throughout New Zealand.

The plant was first described by German naturalist Georg Forster in 1786. U. ferox is pollinated by the wind, and its seeds are later dispersed by gravity or the wind. Several butterfly and moth species can be hosted on the plant, and it is the favoured source of food for the larvae of the New Zealand red admiral (Vanessa gonerilla) butterfly. U. ferox is a plant usually avoided by people, but it did have some traditional and medicinal uses for the indigenous Māori people. U. ferox's 2023 assessment in the New Zealand Threat Classification System was "Not Threatened".