Privet was originally the name for the European semi-evergreen shrub Ligustrum vulgare, and later also for the more reliably evergreen Ligustrum ovalifolium used extensively for privacy hedging. It is often suggested that the name privet is related to private, but the OED states that there is no evidence to support this. The term is now used for all members of the genus Ligustrum, which includes about 40-50 species of evergreen, semi-evergreen or deciduous shrubs and small trees, native to Europe, north Africa, Asia and Australasia, with the centre of diversity in China, the Himalayas, Japan and Taiwan. The generic name was applied by Pliny the Elder (23 CE – 79) to L. vulgare. The genus Ligustrum is placed in the olive family, Oleaceae.
The flowers are small and fragrant and borne in panicles. They have four curled-back petals and two high stamens with yellow or red anthers, between which is the low pistil; the petals and stamens fall off after the flower is fertilized, leaving the pistil in the calyx tube. Flowering starts after 330 growing degree days. The fruits, borne in clusters, are small purple to black drupes. The fruits of some species are mildly poisonous to humans.