Incense Cedar (Decurrens)

The Incense Cedar (Decurrens) is generally described as a perennial tree. This is native to the U.S. (United States) has its most active growth period in the spring and summer . The greatest bloom is usually observed in the late spring, with fruit and seed production starting in the summer and continuing until fall. Leaves are retained year to year. The Incense Cedar (Decurrens) has a long life span relative to most other plant species and a slow growth rate. At maturity, the typical Incense Cedar (Decurrens) will reach up to 100 feet high, with a maximum height at 20 years of 12 feet.

The Incense Cedar (Decurrens) is easily found in nurseries, garden stores and other plant dealers and distributors. It can be propagated by bare root, container, cuttings, seed. It has a slow ability to spread through seed production and the seedlings have low vigor. Note that cold stratification is not required for seed germination and the plant cannot survive exposure to temperatures below -33°F. has medium tolerance to drought and restricted water conditions.

Uses of : Landscaping, Medicinal, Culinary, etc.

Medicinal: A decoction of the leaves was used to treat stomach troubles (Moerman 1998). Steam from an infusion of incense cedar bark was inhaled in the treatment of colds (Ibid.). The bark was used to make baskets and the twigs were used to make brooms.

Economic: Incense cedar has aromatic wood that resists decay and insects. The wood is used as window sashes, sheathing under stucco or brick veneer construction, mudsills, fencing, greenhouse benches, and poles. It is also widely used for interior and exterior siding. The soft and pliable wood makes it one of the few species suitable for making pencils.

Landscaping & Wildlife: Incense cedar is an attractive landscape tree that is excellent for large areas and formal plantings (Dirr 1990). This tree is a splendid park and large home-grounds species in climates suitable for them (Lemmon 1952). It is browsed moderately by mule deer. Small mammals eat the seeds. This species is primarily used by wildlife species for cover.

Agroforestry: Calocedrus decurrens is used in tree strips for windbreaks. It is planted and managed to protect livestock, enhance production, and control soil erosion. Windbreaks can help communities with harsh winter conditions better handle the impact of winter storms and reduce home heating costs during the winter months. Incense cedar is also widely planted in the mountains for erosion control.

General Characteristics

General: Cypress family Cupressaceae. Incense cedar (Calocedrus decurrens is a medium sized tree eighty to one hundred twenty feet high (Preston 1989). The leaves are small, scale-like, oblong-ovate, in whorls of four, decurrent, and closely adnate on the branchlets and aromatic when crushed. The flowers are monecious, appearing in January on the ends of short lateral branchlets of the previous year. The fruit is reddish-brown or yellowish-brown that ripens in the early autumn and remains on the tree until spring. The bark is bright cinnamon-red, broken into irregularly ridges, and covered with closely appressed plate-like scales (Sargent 1961).

Required Growing Conditions

Calocedrus decurrens is native to the mountains from western Oregon in higher Coast Ranges and Sierra Nevada to southern California and western Nevada. For current distribution, please consult the Plant profile page for this species on the PLANTS Web site.

Adaptation Incense cedar prefers moist, well-drained, fertile soil. It grows best in full sun or light shade. This species is not tolerant of smoggy or wind-swept conditions (Dirr 1990). It shows good adaptability to different soil types (Ibid.). This tree is often found in mixed coniferous stands with sugar pine, ponderosa pine, Jeffrey pine, western white pine, white fir, and Douglas fir (Preston 1989).

Cultivation and Care

Propagation for Seed: Sow seeds in the early spring in a greenhouse. Seeds require a stratification period for about eight weeks at 32-40ºF for good germination. When the seedlings are large enough to handle, place them into individual pots to grow in a light shaded area in a greenhouse or cold frame for the first winter. Plant them out in the late spring or early summer.

General Upkeep and Control

Incense cedar has aromatic wood that resists insects and decay. Practically no pests attack the tree but in the forests where it is native, mature tree trunk are often infested with dry rot of the heartwood (Wyman 1965).

In its younger years, especially when growing strongly in the open, incense cedar forms an almost geometrically perfect pyramid, its lower branches nearly touching the ground, and the whole mass so densely overlapping that it sheds both rain and snow (Lemmon 1952). In old age, after battling the elements for perhaps a thousand years, it is far more irregular and picturesque, often with several summits trying to replace the old one destroyed long before lightening or a great wind (Ibid.).

Plant Basics
Growth Rate Slow
General Type Tree
Growth Period Spring, Summer
Growth Duration Perennial
Lifespan Long
Plant Nativity Native to U.S.
Commercial Availability Routinely Available
Physical Characteristics
Bloom Period Late Spring
Displays Fall Colors No
Shape/Growth Form Single Stem
Drought Tolerance Medium
Shade Tolerance Intermediate
Height When Mature 100
Vegetative Spread None
Flower Color Yellow
Flower Conspicuousness No
Fruit/Seed Abundance Medium
Fruit/Seed Seasonality Summer Fall
Seed Spread Rate Slow
Gardening Characteristics
Propagations (Ways to Grow) Bare Root, Container, Cuttings, Seed
Moisture Requirements Low
Cold Stratification Required Yes
Minimum Temperature -33
Soil Depth for Roots 60
Toxic to Nearby Plants No
Toxic to Livestock No
After-Harvest Resprout Ability No
Responds to Coppicing No
Growth Requirements
pH Range 4.6–7.1 pH
Precipitation Range 20–20 inches/yr
Planting Density 300–700 indiv./acre
Soil Textures Coarse, Fine, Medium
Soil Depth for Roots 60
Minimum Frost-Free Days 100 day(s)
Salinity Tolerance None
CaCO3 Tolerance Low
Sustainability & Use
Leaf Retention Yes
Palatability Low
Fire Resistant No

Source: USDA, NRCS, PLANTS Database,
National Plant Data Center, Baton Rouge, LA 70874-4490 USA