A Japanese cedar is a large evergreen tree with a cone shape, that is grown as a specimen tree and by roads. It is originally from Japan, where it is the national tree. It is the only species in the family Cupressaceae and has the scientific name Cryptomeria japonica. Formerly, it was in the family Taxodiaceae, along with the California redwood and the Giant Sequoia, which it resembles. The plant is not a true cedar.
Japanese cedar trees can grow very large, reaching 230 ft (70 m) tall, with a trunk diameter of 13 ft (4 m). In ten years, they can grow up to 25 ft (7.6 m). Due to this, they are often planted along roads, where they can look very stately. The trees can live for hundreds of years.
The bluish-green leaves look like needles and are 0.20-0.39 in (0.5-1 cm) long, arranged in spirals covering the branches. The trees have globular seed cones that are 0.39-0.79 in (1-2 cm) in diameter. The branches grow in horizontal groups. They point upwards at first, then droop near the ends. The bark is reddish-brown and forms long strips that peel off from the tree.
Japanese cedar is grown in many places around the world. It is widely grown in Japan and China, and is also grown in the United States, Europe, and parts of India and Nepal. In the United States, it can be grown in USDA Zones 6-9. There are over 200 cultivars available in Japan, but Western gardeners have fewer to choose from. Many dwarf varieties are popular, and Japanese cedar bonsai trees are highly prized.
The trees should generally be grown in full sun, although they should have partial shade in warmer climates. They prefer to be kept moist, although they do exhibit some drought tolerance. Japanese cedar trees will tolerate compacted soil, making it a good tree for parking lots and medians. They also make good windbreaks. If the trees get too tall, they can be cut down and will re-grow.
Propagation of the Japanese cedar tree is best done by layering, since growth from seeds can be difficult. It is possible to put part of a branch in a pot and water it occasionally, and it will sprout roots. Then, once the new plant has grown, one can cut off the original branch. The young plant should be left to grow for a few months before being transplanted.
Japanese cedar trees are grown for lumber, since their wood is waterproof, lightweight, and resistant to decay. There are large plantations in China, Japan, and the Azores Islands. In the Azores Islands, the trees have become invasive and have overgrown the native vegetation. In Japan, the trees are frequently planted around shrines and temples.