Juniperus chinensis aka Chinese Juniper

Chinese juniper, Juniperus chinensis, is an evergreen conifer in the cypress family, Cupressaceae. It grows wild across eastern Asia. Its range includes China, Mongolia, Korea, Japan and the Himalayas. It also reaches Taiwan, Myanmar and the Russian Far East. The species itself is rarely sold, but gardeners grow dozens of its cultivars.

In the wild it forms a narrow, conical tree of 50 to 60 feet (15 to 18 metres) tall. One source records trees up to 70 feet (21 metres). Spread runs from about 15 to 20 feet (4.5 to 6 metres). The species is very variable, and some wild plants stay as low, spreading shrubs. Garden selections range from flat groundcovers through compact shrubs to upright trees. Growth is slow to medium.

The plant carries two kinds of foliage, often on the same specimen. Young growth has sharp, awl-shaped needles about a third of an inch long. These sit in pairs or in threes. Mature growth has tiny scale-like leaves pressed flat against the twig in opposite pairs. The foliage ranges from dark green to blue-green or grey-green and smells pungent when crushed. Light brown bark forms ridges and peels away in thin strips.

Junipers do not produce true flowers. Male and female cones usually grow on separate plants, and the wind carries the pollen. Small yellowish pollen cones appear in early spring. Female plants bear round, fleshy cones that resemble berries, up to half an inch (12 mm) across. These start pale blue and take two seasons to ripen to violet, brown or near black. Birds feed on them.

Chinese juniper does best in full sun and tolerates some shade. It grows in chalk, clay, loam or sand, from acid to alkaline. Good drainage matters most, because waterlogged soil leads to root rot. Once established, it copes with drought, rocky ground, heat, salt spray and city air pollution. Deer rarely browse it, and it moves easily when transplanted. It is hardy in USDA zones 4 to 9, and some cultivars handle zone 3. The RHS rates it H6, so it survives the coldest UK winters. It needs no routine pruning.

Gardeners choose cultivars to suit the site. Uses include specimens, hedges, screens, mass plantings, groundcover and bonsai. The plant also gives winter interest and helps control erosion. Several diseases can affect it. Kabatina and Phomopsis blights cause shoot dieback, and cultivars differ in how badly they suffer. The plant also hosts cedar-apple rust, which forms orange galls in spring and then infects nearby apple trees. Canker, phytophthora and honey fungus can also strike. Pests include aphids, scale insects, bagworms, webworms, caterpillars and conifer red spider mite.

Sources disagree on edibility. One extension service says cooks use the immature cones as a seasoning. Another source lists no edible uses and no known hazards. The RHS warns that the plant is harmful if eaten and can irritate skin, so wear gloves when handling it. Traditional Chinese medicine has used the stems, fruit, roots and resin.