Juniperus communis, commonly called common juniper, is a dioecious, needled, evergreen conifer that grows in a variety of different shapes and forms in cool to cold areas of the Northern Hemisphere plus in one isolated population growing in the Atlas Mountains of Africa.
Common juniper is a gymnosperm. It is the most widely distributed woody plant on the planet. It forms a great girdle around the cool temperate regions of the northern hemisphere. Despite such a wide distribution it is locally threatened, especially in parts of the United Kingdom, through changing patterns of land use, whilst in other parts of the world it is an invasive.
Common juniper is readily recognised by the triplets of green or blue-green, wax-covered, needle-like leaves that form rings along the young stems. Unlike many members of the genus Juniperus, needle-like leaves are retained throughout the plant's life; in other Juniperus species mature plants have scale-like leaves.
Common juniper has separate male and female plants. Male plants have tiny, yellow cones that shed wind-dispersed pollen. Female plants have berry-like, fleshy seed cones that become purple-black, with a waxy bloom, on maturity. Each seed cone comprises about three fused scales, each with an associated seed. Seeds are usually bird dispersed.
Females cones are used widely as a flavouring in cooking, especially game, and most famously in flavouring gin. In 1751, the cartoonist and printmaker William Hogarth published the famous print Gin Lane, in direct support of the Gin Act; he portrayed its denizens as unhappy, feckless and lazy. Another of juniper's uses - as an abortifacient - is reflected in one of its forthright English common names, 'bastard killer'. The wood is hard, dense and highly scented but individual pieces are too small to have significant commercial value, except in certain types of decorative work. The oil is sometimes used to treat skin conditions.