Overview
Tutu is the common Māori name for several species of the flowering plant genus Coriaria, members of the family Coriariaceae, that grow in New Zealand. The word comes from Māori usage and applies to a group of shrubs and small trees recognized for their attractive clusters of fruit and, importantly, for their toxicity.

Characteristics and species

Tutu plants vary from low-growing bushy forms to small trees. Many are woody and have simple leaves and clusters of small flowers that develop into small berry-like fruits. Several species native to New Zealand are commonly called tutu; among them are:

Some of these are endemic to New Zealand, while the wider genus also has relatives in parts of Asia, the Mediterranean region and South America. Growth habit ranges from low shrub to multi-stemmed trees; in general the plants are regarded as shrubs or trees depending on species and site.

Toxicity and the neurotoxin tutin

Most parts of tutu are poisonous. The primary toxin, called tutin, is a potent neurotoxin present in the sap and seeds. Animals, especially cattle, were historically vulnerable when grazing in areas with tutu plants; shepherds and farmers in early European settlement periods reported stock deaths after consuming parts of the plant.

Traditional uses and food processing

Despite the toxicity, Māori developed careful traditional processing techniques to use the fruit. After removing poisonous seeds, the sweet pulp was sometimes boiled with seaweed such as rimu to make a jelly called rehia, which could then be consumed fresh or fermented. These preparations required intimate knowledge of the plant and careful handling to avoid poisoning.

Toxic honey and the role of insects

Tutin can enter the human food chain indirectly through honey. The pathway involves sap-feeding insects: vine hopper bugs feed on tutu and excrete a sugary secretion known as honeydew. Honey bees collect this honeydew along with nectar; if the honeydew contains tutin derived from the plant sap, the resulting honey can be toxic. Outbreaks of toxic honey poisoning have been documented historically and sporadically in more recent times, with serious symptoms including vomiting, delirium and, in severe cases, coma.

Management, risks and notable facts

Because of the risk to livestock and the potential for contaminated honey, tutu is treated with caution in areas where it grows. Beekeepers monitor hive sources and local flowering and honeydew events to reduce risk. Botanically, tutu is notable for combining attractive fruiting displays with powerful chemical defenses — an important reminder that not all colorful or sweet-appearing plant parts are safe to eat without specific knowledge or processing.

For further botanical or horticultural details see general references on the genus Coriaria and regional plant guides; for cultural history consult resources on Māori plant use and traditional foods.