Tree · Cupressaceae
Japanese Cedar
Cryptomeria japonica
Give it rich, moist soil and shelter from winter wind, and Japanese cedar climbs into a towering evergreen spire of feathery green.
Full sun
Every 7–14 days
USDA 5–9
50–70 ft · 15.2–21.3 m
Overview
Japanese cedar is the national tree of Japan, where it is known as sugi and lines temple grounds in tall, stately rows. Up close it is all soft texture: feathery, awl-shaped needles that curve out and spiral tightly around every shoot, giving the branches a plush, blue-green to deep-green sheen. Despite the name, it is no true cedar but a member of the cypress and redwood family, standing alone in its own genus.
The tree carries real weight in the landscape. Grown out, it climbs to 50 to 70 feet (15 to 21 m) in a broad pyramidal crown, and the trunk is its own spectacle, wrapped in reddish-brown bark that peels in long, shaggy strips you can catch and pull loose in ribbons. Cold-hardy to -20°F (-29°C), it holds that dense green through USDA zones 5 to 9 while the small, round, woody cones ripen at the tips in fall.
Most gardeners plant a named cultivar rather than the wild form, and the variety in needle and shape is striking. Some hold as tight dwarf globes of stubby foliage, while full-size selections rise into fast, dense walls of green. Whatever the form, the tree wants steady moisture and shelter from the harshest wind, and from there it needs little fuss.
Care
The short version: full sun to light shade, in rich, moist, acidic, well-drained soil that never dries out, with a planting spot sheltered from harsh, drying winter wind.
Light
Japanese cedar grows best in full sun, which keeps the feathery canopy dense and even in color. It will take partial sun or light shade, but in a shadier spot the foliage thins and the shoots stretch loose and open.
Water
Keep the soil consistently moist, above all while the tree is young, and never let it dry out. Watering every 7 to 14 days suits most settings, and an established tree carries a brief dry spell. What it will not tolerate is real drought.
Soil
Plant it in rich, deep, moist, well-drained loam on the acidic side, ideally a pH of 5.0 to 6.5. The soil should hold moisture without turning waterlogged, so work in organic matter on heavy or thin ground.
Temperature
This is a tough tree, hardy from -20°F to 100°F (-29°C to 38°C) across USDA zones 5 to 9. It shrugs off summer heat and deep winter cold alike, though drying winter wind bronzes the needles more than the cold itself.
Humidity
Average outdoor humidity is all it needs, so there is no number to track. Steady soil moisture matters far more than what the air is doing.
Feeding
Feed in spring with a balanced or acid-forming slow-release fertilizer made for evergreens. Once a season is plenty for a healthy tree, and overdoing it only pushes soft, weak new shoots.
Pruning
Japanese cedar needs little pruning. Clip out any dead, damaged, or winter-burned shoots in spring, and that is usually the whole job. It also takes shearing well, tightening into a clean green wall for a screen or hedge.
Repotting
Most Japanese cedars live in the ground and never need repotting. For one kept in a container, repot rarely, and watch for roots circling the pot, water rushing straight through, or stalled new growth as your cue.
Size & spacing
Plan for a tree that reaches 50 to 70 feet (15 to 21 m) tall with a spread of 20 to 30 feet (6 to 9 m). Give it that much room from buildings and other trees, or step down to a dwarf cultivar for a tighter spot.
When to plant
Japanese cedar is an evergreen conifer that holds its needles year round, so there is no sowing season to chase and no harvest to time. Plant it in spring or early fall, while the soil is warm and moisture reliable, so the roots stretch out through a run of mild weather before they meet heat or hard cold.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Plant: Spring or early fall
- Harvest: Non-flowering; grown for evergreen foliage and form (cones mature in fall)
Hardiness
USDA hardiness zones: 5–9
Temperature: down to -29°C
Troubleshooting
Japanese cedar is an easy, low-maintenance tree, and the few troubles it meets show up right there in the needles, in a shift of color or a blotch on the foliage. Most are cosmetic and fade with the season. Match what you see against the notes below before deciding whether to act.
Needles turning bronze and purplish, as if scorched
Most often the color you see is winter bronzing, a seasonal shift that runs the green needles to bronze and purple before they flush back to green in spring. The change bites deepest on the windward side, where dry winter wind draws moisture out of the fine needles faster than the frozen roots can send it back. Give the tree a windbreak, carry it into winter with damp soil, and cut away any shoots that stay a dead brown once the new growth pushes.
Fix:
- Site plants where they are sheltered from harsh, drying winter winds
- Keep soil adequately moist going into winter
- Prune out shoots that fail to green up in spring
Brown blotches on the needles and dead twig tips
The brown spots and blotches are the mark of leaf spot and leaf blight fungi, Cercospora and Pestalotiopsis among them, which take hold in the still, moist air deep among the lower inner branches. They fasten onto a stressed tree first, so a plant struggling in a poor spot or a dry stretch shows the discolored, blighted needles soonest. Cut out the spotted twigs, open the crowded branches so air can slip through, and keep the tree in good health, since the blemish is skin deep rather than deadly.
Fix:
- Prune out and dispose of affected twigs and foliage
- Improve air circulation and avoid overhead wetting of foliage
- Maintain plant vigor with proper siting, water, and nutrition
Toxicity
Good news for pet owners: Japanese cedar is not toxic. It appears on no poison list, and animals can live alongside it without risk. The only thing to mind is the foliage itself, since the fine needles end in stiff, sharp points.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
The tree holds no known toxin, so a cat is safe beside its feathery sprays of needles. A cat that mouths the foliage might drool or have a brief stomach upset, the same as with any stiff, coarse greenery.
Dogs None
Japanese cedar sits on no poison list, so a dog is safe around its needle-clad shoots. A pup that chews a fallen sprig of the pointed foliage may get a passing bout of mild stomach trouble and nothing worse.
Horses Safe
The tree holds no toxic threat for horses. Its needles are stiff and awl-shaped, sharp little points that most horses leave well alone.
Rabbits Safe
No harmful compound has been recorded in this conifer, so rabbits are not at risk. The prickly, sharp-tipped foliage rarely tempts them to nibble in the first place.
Livestock Safe
Cattle, goats, and sheep can graze nearby with no danger of poisoning. The sharp, resinous needles are a stiff, unappealing mouthful, so they seldom bother with it.
Birds Safe
Nothing in the needles or the small woody cones is toxic to birds, which come to no harm from it. They often tuck into the dense, feathery evergreen cover for shelter.
People Safe
Japanese cedar is safe to plant and handle, though the fine, awl-shaped needles end in sharp points that can prick bare skin. It bears no edible part and is grown for its shade and evergreen screen rather than for the table.
Foliage is harmless to handle, though needles are sharply pointed and awl-shaped.
Varieties
The straight species grows large, so most gardeners pick a cultivar that fits the space, and each brings its own needle color and shape. These are the ones you will run into most often.
Yoshino
A vigorous, fast grower of about 30 to 40 feet whose blue-green needles keep their cool color through winter with far less of the usual bronzing.
Black Dragon
A dwarf whose very dark green foliage packs into an upright, dense pyramid with a slightly ragged, irregular outline.
Globosa Nana
A slow, rounded dwarf shrub of about 2 to 4 feet whose bluish-green needles take on a rusty-red cast when winter cold sets in.
Sekkan-sugi
Grown for the soft creamy-yellow new growth that glows at the very tips of the branches.
Radicans
A fast, narrow pyramid clothed in rich blue-green needles that make it a favorite for a dense screen.
How to propagate
You can raise Japanese cedar from seed, cuttings, or layering, and the method you choose depends on whether you want a true copy of a named cultivar or simply more trees.
SeedModerate
Sow in fall or spring after cold stratification · Several months to germinate; years to reach landscape size
Seed sown in fall or spring after a cold stratification will sprout into slender green seedlings, but the process is slow, taking several months to germinate and years for the trees to reach landscape size. Those seedlings come out variable in form and color, so named cultivars never breed true this way.
Stem cuttingsModerate
Semi-hardwood cuttings in late summer to fall · Several weeks to months to root
Cuttings copy a named cultivar exactly, needles and habit alike. Take firm semi-hardwood cuttings of the leafy shoots from late summer into fall, dip the cut ends in rooting hormone, and hold them in humid air while roots form over the following weeks to months.
LayeringModerate
Spring · One or more seasons
A low, feathery branch resting on the soil will strike roots where it touches. Pin one down in spring, let it root in place, and give it a season or more before the new plant is cut free.
Myths
Japanese cedar is a true cedar.
The name aside, this tree has no kinship with the true cedars of the genus Cedrus. Cryptomeria keeps its own genus within the cypress and redwood family, Cupressaceae. The common name is a misnomer, not a clue to its family.