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Publication #ENH-787

 

Thuja occidentalis: White-Cedar1

Edward F. Gilman and Dennis G. Watson2

Introduction

This slow-growing tree reaches 25 to 40 feet in height and spreads to about 10 to 12 feet wide, preferring a wet or moist, rich soil. Transplanting is moderately easy if plants are root-pruned and either balled and burlapped or potted. White-Cedar likes high humidity and tolerates wet soils and some drought. The foliage turns brownish in winter, especially on cultivars with colored foliage and on exposed sites open to the wind.

Figure 1. 

Middle-aged Thuja occidentalis: White-Cedar


[Click thumbnail to enlarge.]

General Information

Scientific name: Thuja occidentalis
Pronunciation: THOO-yuh ock-sih-den-TAY-liss
Common name(s): White-Cedar, Arborvitae, Northern White-Cedar
Family: Cupressaceae
USDA hardiness zones: 2A through 7B (Fig. 2)
Origin: native to North America
Invasive potential: little invasive potential
Uses: screen; hedge; specimen; reclamation; highway median
Availability: somewhat available, may have to go out of the region to find the tree

Figure 2. 

Range


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Description

Height: 25 to 40 feet
Spread: 10 to 12 feet
Crown uniformity: symmetrical
Crown shape: pyramidal
Crown density: dense
Growth rate: slow
Texture: fine

Foliage

Leaf arrangement: alternate (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: yellow
Flower characteristics: not showy

Fruit

Fruit shape: cone, oval
Fruit length: less than .5 inch
Fruit covering: dry or hard
Fruit color: brown
Fruit characteristics: does not attract wildlife; not showy; fruit/leaves not a litter problem

Trunk and Branches

Trunk/bark/branches: branches don't droop; not 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: 0.31

Culture

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

Other

Roots: not a problem
Winter interest: no
Outstanding tree: no
Ozone sensitivity: tolerant
Verticillium wilt susceptibility: resistant
Pest resistance: sensitive to pests/diseases

Figure 3. 

Foliage


[Click thumbnail to enlarge.]

Use and Management

Best used as a screen or hedge planted on 8 to 10-foot-centers. There are better specimen plants but it can be placed at the corner of a building or other area to soften a view. Many of the natural stands in the United States have been cut. Some remain in isolated areas along rivers throughout the East.

White-Cedar has given rise to many cultivars, many of which are shrubs. Cultivars include: `Booth Globe' - low, rounded with a flat top; `Compacta' - dense and compact; `Compacta Erecta' - semi-dwarf, pyramidal; `Douglasi Pyramidalis' - dense, columnar; `Emerald Green' - good winter color; `Ericoides' - dwarf, brownish foliage in winter; `Fastigiata' - narrow, columnar; `Globosa' - dense, rounded; `Hetz Junior' - dwarf, wider than it is tall; `Hetz Midget' - slow grower, quite dwarf, rounded; `Hovey' - low and rounded; `Little Champion' - globe shaped; `Lutea' - yellow foliage; `Nigra' - dark green foliage in winter, pyramidal; `Pumila' (Little Gem) - rounded, dwarf; `Pyramidalis' - narrow pyramidal form; `Rheingold' - rounded form with yellow to bronze new growth; `Rosenthalli' - dense, pyramidal; `Techny' - pyramidal, dark green, hardy; `Umbraculifera' - flat topped; `Wareana' - low and dense, pyramidal; `Woodwardii' - rounded and spreading.

Pests

Arborvitae leaf miner mines out the leaf tips, causing them to turn brown. Translucent areas are seen where the miner has been active.

Scales of several types infest the stems and foliage. Sprays of horticultural oil control overwintering stages.

Mites cause yellowing and speckling of the foliage. The mites are seldom noticed because they are so small.

Bagworms can devour large quantities of foliage very quickly.

Diseases

Leaf blight causes brown spots on the leaves in late spring. The affected foliage appears scorched, then drops.

Footnotes

1.

This document is ENH-787, one of a series of the Environmental Horticulture, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Original publication date November 1993. Revised December 2006. Reviewed May 2011. Visit the EDIS website at http://edis.ifas.ufl.edu.

2.

Edward F. Gilman, professor, Environmental Horticulture Department; Dennis G. Watson, former 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. Nick T. Place, Dean.