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Publication #ENH272

Calocedrus decurrens: California Incense-Cedar1

Edward F. Gilman and Dennis G. Watson2

Introduction

This stately native evergreen tree slowly grows straight up in a very narrow cone or columnar shape to a height of 70 to 100 feet or more in the wild, 40 to 60 feet in landscapes, yet is only 8 to 12 feet wide at maturity. The branches, which are densely clothed with flat, shiny, dark green, aromatic needles, extend to the ground and remain on the tree unless shaded-out by other trees, making California Incense-Cedar ideal for use as a screen, hedge, or windbreak. Small, one-inch-long cones are produced at branch tips and are quite persistent, the seeds providing a welcome treat for many varieties of birds and wildlife. Although growth is slow, California Incense-Cedar trees are extremely long-lived, surviving 500 to 1000 years in the wild. Mature specimens have attractive, brick red, flaky, furrowed bark.

Figure 1. 

Middle-aged Calocedrus decurrens: California Incense-Cedar

General Information

Scientific name: Calocedrus decurrens
Pronunciation: kal-oh-SEE-drus deck-ER-renz
Common name(s): California Incense-Cedar
Family: Cupressaceae
USDA hardiness zones: 5A through 8B (Fig. 2)
Origin: native to North America
Invasive potential: little invasive potential
Uses: screen; hedge; specimen
Availability: somewhat available, may have to go out of the region to find the tree

Figure 2. 

Range

Description

Height: 40 to 60 feet
Spread: 8 to 12 feet
Crown uniformity: symmetrical
Crown shape: pyramidal, columnar
Crown density: dense
Growth rate: slow
Texture: fine

Foliage

Leaf arrangement: opposite/subopposite (Fig. 3)
Leaf type: simple
Leaf margin: entire
Leaf shape: scale-like
Leaf venation: none, or difficult to see
Leaf type and persistence: evergreen, fragrant
Leaf blade length: less than 2 inches
Leaf color: green
Fall color: no color change
Fall characteristic: not showy

Flower

Flower color: unknown
Flower characteristics: not showy

Fruit

Fruit shape: elongated, oval
Fruit length: .5 to 1 inch
Fruit covering: dry or hard
Fruit color: brown
Fruit characteristics: attracts birds; not showy; fruit/leaves not a litter problem

Trunk and Branches

Trunk/bark/branches: branches don't droop; very showy; typically one trunk; thorns
Pruning requirement: little required
Breakage: resistant
Current year twig color: green, brown
Current year twig thickness: thin
Wood specific gravity: 0.37

Culture

Light requirement: full sun, partial sun or partial shade
Soil tolerances: clay; sand; loam; acidic; slightly alkaline; well-drained
Drought tolerance: high
Aerosol salt tolerance: high

Other

Roots: not a problem
Winter interest: no
Outstanding tree: yes
Ozone sensitivity: unknown
Verticillium wilt susceptibility: resistant

Pest resistance: resistant to pests/diseases

Use and Management

California Incense-Cedar is a bit particular as to its growing requirements, being very sensitive to continually wet conditions. But with the right combination of proper humidity and moist soil, California Incense-Cedar will be quite happy growing in full sun or partial shade with some protection from harsh winds. It is surprisingly tolerant of heat and drought. Pruning is rarely necessary but trees may be sheared, if desired, to maintain a shorter, denser screen. Beautiful specimens of this tree can be seen growing in USDA hardiness zones six and 7.

Many plants grown seem to be the cultivar `Columnaris', having a very formal landscape effect. The cultivar `Compacta' has a dwarf, compact growth habit; `Aureovariegata' has interspersed sprays of bright yellow foliage.

Propagation is by seed or cuttings (with great difficulty) or grafted onto Thuja occidentalis .

Pests

No pests are of major concern.

Diseases

A serious problem is heart rot, less serious problems are rust and leafy mistletoe.

Footnotes

1.

This document is ENH272, one of a series of the Environmental Horticulture Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Original publication date November 1993. Revised December 2006. Visit the EDIS Web Site at http://edis.ifas.ufl.edu.

2.

Edward F. Gilman, professor, Environmental Horticulture Department; Dennis G. Watson, associate professor, Agricultural Engineering Department, Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville FL 32611.

The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other extension publications, contact your county Cooperative Extension service.

U.S. Department of Agriculture, Cooperative Extension Service, University of Florida, IFAS, Florida A. & M. University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Millie Ferrer-Chancy, Interim Dean.