A genus of 7 evergreen coniferous trees from North America and eastern Asia. They are of pyramidal to columnar habit with flattened, fern-like branchlets. The adult leaves are scale-like and in opposite pairs, those of each other pair (median or facial leaves) pressed flat to the stem, those in between folded and keeled. Juvenile leaves (those of seedlings and young plants) are very different, being larger and awl-shaped to linear, often blue-grey-tinted. In some individuals this juvenile foliage is retained indefinitely. The strobili (flower clusters or spikes) are very small, the males ovoid, often red or yellow, the females globular and green or glaucous. The latter become small cones composed of six to twelve woody, peltate scales, each sheltering two to five winged or angled seeds.
All the true species are far too large for the rock garden but most of them have given rise to a number of pygmy to dwarf mutant cultivars which make valuable specimen plants for the rock garden, raised bed and alpine house. They require well drained but not dry, preferably humus-rich soil and full sun to half day shade. Propagation is by cuttings of lateral shoots in autumn or spring. Autumn cuttings should be taken with a heel and placed in a cold frame. Spring cuttings are best without a heel and need bottom heat, ideally with mist. Dwarf cultivars do not come true to type from seed.