Barberry is a deciduous shrub native to parts of Europe, Africa, and Asia, and now naturalized in North America, the British Isles, and cultivated in New Zealand. The shrub's small oblong red berries are an important food source for birds and are sometimes eaten by humans, although the thorny bush makes harvesting the berries difficult. Iran is the largest barber producer and consumer, with the berries found in traditional Persian chicken dishes, rice, jam, juice, and fruit rolls.