Incense Cedar (Calocedrus decurrens) care guide

Calocedrus decurrens is commonly called Incense Cedar. It is an aromatic evergreen conifer in the cypress family, Cupressaceae, and is native to the western United States.

Incense Cedar generally has a medium growth rate, although growth varies with climate, soil depth, moisture, and competition. Young trees establish more slowly in drought-prone or compacted sites.

In cultivation, Incense Cedar commonly reaches about 30 to 70 feet tall and 10 to 20 feet wide. In favorable natural conditions, mature trees can become considerably larger.

Yes, Incense Cedar is an evergreen tree with flattened, scale-like sprays of foliage. Older inner foliage may brown and shed naturally, especially in autumn.

Incense Cedar grows in full sun to partial shade. Full sun supports the densest, most symmetrical growth, while young trees can tolerate some protection from intense heat or wind.

Established Incense Cedar is generally suited to USDA Zones 5 through 8, depending on local conditions and plant provenance. It can tolerate temperatures near -22°F when established, but young trees need more protection from severe cold.

Yes, established Incense Cedar is highly drought tolerant. Water it regularly during the first few growing seasons, then reduce irrigation once the root system is well established.

Incense Cedar can grow in clay loam and other clay-based soils if drainage is good. Avoid sites where heavy clay stays saturated, because the tree is sensitive to continually wet conditions.

The best soil is deep, well-drained sandy loam, loam, or clay loam. It tolerates a relatively broad pH range, but poor drainage is more problematic than moderately acidic or alkaline soil.

Plant Incense Cedar well away from buildings, overhead wires, sidewalks, and other permanent structures because it becomes a large tree. A site with ample vertical and horizontal clearance is preferable to a narrow foundation bed.

Yes, Incense Cedar can provide an evergreen screen, particularly where there is enough room for its mature width. Space trees according to their expected mature size rather than their nursery-container size.

Water deeply when the soil begins to dry during establishment, usually once or twice weekly during hot, dry periods. After establishment, irrigate only during prolonged drought, extreme heat, or unusually dry winters.

Browning may result from drought stress, root damage, poor drainage, winter injury, pests, or disease. Inspect whether browning is limited to older inner foliage or occurs on entire branches, and address watering or drainage problems first.

Incense Cedar usually does not need routine fertilizer when planted in reasonably fertile soil. Test the soil before feeding, because unnecessary fertilizer can promote weak growth or aggravate root stress.

Incense Cedar is generally not troubled by major insect pests, but weakened trees may attract bark beetles or wood-boring insects. Cone insects, scale insects, and western conifer seed bugs may occur but are usually less serious on healthy trees.

Important problems include heart or pocket dry rot, root diseases, rust, and leafy mistletoe. Preventing trunk wounds, avoiding saturated soil, and maintaining overall tree vigor can reduce risk, but advanced heart rot may require an arborist assessment.

No, Incense Cedar does not perform well in continually wet or poorly drained soil. Improve drainage or choose a better-drained planting site before planting rather than relying on frequent amendments after the tree is established.

Plant Incense Cedar in fall or early spring when temperatures are mild and soil moisture is dependable. Avoid planting during frozen soil, extreme summer heat, or extended drought unless reliable irrigation is available.

Dig a broad hole no deeper than the root ball, set the tree with its root flare at or slightly above grade, and backfill with the native soil. Water thoroughly, apply a few inches of mulch without touching the trunk, and keep the root zone evenly moist during establishment.

Incense Cedar is not a good long-term container plant because it develops into a large tree and eventually needs substantial root space. A container may be suitable temporarily for a young nursery tree before planting it in the landscape.

Incense Cedar is not generally considered to have unusually aggressive surface roots. However, any large tree can affect nearby paving, foundations, irrigation lines, or other plants when planted in a confined space.

Propagate Incense Cedar primarily from seed collected from mature cones. Cold-stratify the seed at about 37–41°F for roughly eight weeks, or sow fresh seed in fall, then plant it shallowly in a well-drained medium.

Incense Cedar can be propagated from cuttings, but rooting is difficult and generally less reliable than growing it from seed. Commercial propagation may also use grafting for selected cultivars.

Collect Incense Cedar seeds from mature cones in late summer or early fall, when the cones have developed their brown coloration and begin releasing seed. Store cleaned seed in a cool, dry place if it will not be sown promptly.

Prune Incense Cedar mainly to remove dead, damaged, diseased, crossing, or poorly attached branches. Make proper cuts outside the branch collar and avoid topping or removing large amounts of live foliage from the tree at once.

Incense Cedar can be lightly sheared to maintain a denser or more formal shape, especially when young. Repeated severe shearing is undesirable because old interior wood may not reliably produce new foliage.

The toxicity of Calocedrus decurrens is insufficiently documented in the available horticultural references. Avoid ingestion, prevent pets and children from chewing the foliage or cones, and contact a veterinarian or poison-control service if plant material is swallowed.

Incense Cedar produces small, inconspicuous male and female reproductive structures rather than showy flowers. It is wind-pollinated, with pollen released in late winter or early spring.

Seed cones mature in late summer and become brown or reddish brown as they develop. Each small cone contains only a few winged seeds that are dispersed mainly by wind.

Yes, Incense Cedar has aromatic foliage and wood, especially when the foliage is crushed or the wood is freshly cut. The fragrance is one of its notable ornamental and cultural features.