730 Cryptomeria japonicaCommon Names: Japanese cedar, sugi Family: Taxodiaceae (bald-cypress Family)
Japanese cedar is a tall, cone shaped evergreen with bluish green foliage and a massive trunk with thick reddish brown bark that shreds and peels in long strips. This is a fast growing tree that, in its native habitat, can get more than 180 ft (55 m) tall with a trunk diameter exceeding 12 ft (3.7 m); ornamental specimens are rarely more than 60 ft (18 m) tall though, and many of the named selections stay much smaller. The branches are arranged in horizontal tiers, ascending at first, then drooping near their ends. The flattened, wedge-shaped leaves are about 0.5 in (1.3 cm) long and point forward, while their bases clasp the twigs. The leaves are overlapping and crowded in 5 ranks that spiral around and completely cloak the twigs. Male and female cones, 1 in (2.5 cm) or less in length, are on the same tree. Two varieties are recognized: var. japonica has a dense habit and thick, spreading branches; var. sinensis has a looser habit and slender, drooping branches. More than 200 ornamental cultivars have been named; most probably were selected from var. sinensis. 'Elegans', perhaps the best known of the larger cultivars, has soft, blue-green shrubby foliage turning bronze in winter; it gets up to 30 ft (9.1 m) tall and only 8 ft (2.4 m) wide. 'Elegans Compacta' is similar but stays below 12 ft (3.7 m) in height. 'Cristata' produces some shoots that are fused and flattened into strange "cock's combs." 'Lycopodiodes' has long, thin, drooping branches. 'Globosa Nana' grows in a dense fluffy sphere, to 10 ft (3.1 m) across; 'Compressa' is a dwarf, flat-topped shrub. 'Vilmoriniana' never gets more than 30 in (76.2 cm) tall! 'Variegata' has yellow-variegated leaves. 'Knaptonensis' has white-variegated leaves.
The wild Japanese cedar (Cryptomeria japonica) is a forest tree native to Japan and southern China. The best stands grow on the lower slopes of mountains where annual rainfall is high.
CultureJapanese cedar can grow to 25 ft (7.6 m) tall in just 10 years. Light: Plant Japanese cedar in full sun to partial shade. Moisture: Japanese cedar needs well drained soil but plenty of water for best growth. Never allow the soil to dry out and mist if the humidity stays very low. Hardiness: USDA Zones 6 - 9. In zones 6 and 7, expect the foliage to turn brown or purplish in winter. Propagation: Japanese cedar can be difficult to grow from seed. Named cultivars are propagated vegetatively by rooting mature tip cuttings in late summer or autumn, or by layering. To start a new plant by layering, cram a section of branch into a pot or bury it in the ground. Water occasionally and in a couple of months the potted section will have roots, and you can sever the branch from the mother plant. Allow it establish for another month or two before moving. Young, well rooted specimens transplant easily.
Sugi, as it is called in Japan, has been cultivated as an ornamental for centuries and Japanese gardeners have more than 200 cultivars to select from; most of these are not available in the West. The stately Japanese cedar makes an imposing specimen. Use them in a group to create a visual screen or windbreak. Japanese cedars, symmetrical and uniform, are often planted along avenues. The smaller, shrubby cultivars are useful accent plants or anchors in mixed borders. Japanese cedar is highly prized for bonsai, and the wild form is harvested commercially for timber.
Japanese cedar is one of very few conifers that will coppice - sprout back from cut stumps. You can regenerate an old specimen by cutting back the trunk to 2-3' (0.6-0.9 m) above ground, then selecting which sprout(s) to keep and which to cut. The very fast growing Japanese cedar is especially useful for screens and windbreaks. When they get too tall, cut them back and let them start over!
Cryptomeria japonica is the only species in its genus, and Cryptomeria is one of only 10 genera in the ancient family, Taxodiaceae, which once shared the landscape with the dinosaurs. Today these strange and wonderful trees (only 18 species in the whole family) occur nowhere but eastern Asia, North America and Tasmania! Some well-known species in the Taxodiaceae are the dawn redwood (Metasequoia glyptostrobiodes), California redwood (Sequoia sempervirens), giant sequoia (Sequoiadendron giganteum), and baldcypress (Taxodium distichus).
Steve Christman 7/12/00; updated 11/4/04; 5/6/06