Identifying and Managing Northern White Cedar (Thuja occidentalis)
A thorough guide for recognizing, cultivating, and caring for the Northern White Cedar (Thuja occidentalis) in North American landscapes.
The Northern White Cedar (Thuja occidentalis), also known as arborvitae, is an iconic conifer native to North America. Esteemed for its longevity, resilience, and ecological importance, this tree is favored for landscaping, wildlife support, and practical wood uses. This comprehensive guide covers how to identify, cultivate, and manage Northern White Cedar, while providing insight into its distinguishing features, landscape uses, vulnerabilities, and much more.
What Is Northern White Cedar?
The Northern White Cedar is a slow-growing, medium-sized evergreen tree belonging to the cypress family (Cupressaceae). Recognized for its pyramidal form and scale-like leaves, it inhabits a wide range in northeastern North America. Arborvitae, meaning “tree of life,” highlights its long-held reputation for hardiness and utility.
- Scientific Name: Thuja occidentalis
- Family: Cupressaceae
- USDA Hardiness Zones: 2 to 7
- Common Names: Northern White Cedar, Arborvitae, Eastern White Cedar
How to Identify Northern White Cedar
Identifying Northern White Cedar involves examining its size, shape, bark, foliage, cones, and overall growth pattern.
Key Identification Features
| Feature | Description |
|---|---|
| Height & Spread | Typically 20–60 feet tall, 10–15 feet wide; can grow larger under ideal conditions |
| Form | Compact, pyramidal or conical shape; symmetrical when grown in the open |
| Bark | Gray to reddish-brown, separates in long, vertical, shreddy strips |
| Leaves | Evergreen, scale-like, flat and arranged in fan-shaped sprays; aromatic when crushed |
| Cones | Small, oblong cones (½ inch long), yellowish-brown, with 6–12 scales; grow in clusters at branch tips |
| Roots | Shallow, spreading in moist soil; may develop deeper taproots in drier sites |
Detailed Parts Description
- Bark: Thin, shreddy, fibrous; peels in narrow strips revealing reddish-brown hue underneath.
- Leaves: Scales are 1/16–1/4 inch long, arranged closely to form flat sheets; color varies from green to yellow-green, sometimes turning bronzy in winter.
- Cones & Seeds: Female cones are ellipsoid and upright, turning from green to brown as they mature; each contains a few winged seeds that are wind-dispersed.
- Fragrance: Entire plant exudes a pleasant, spicy-sweet aroma, especially when leaves are crushed.
- Growth Habit: Trunks often twisted, multi-stemmed, forming dense thickets in the wild. In the open, a single stem develops a more pronounced conical top.
Natural Habitat and Range
Northern White Cedar is found throughout the northern United States and much of southern Canada. While most common in the Great Lakes region and New England, its range extends west to Manitoba, south along the Appalachian mountains, and as far as Tennessee and North Carolina (where it is now rare).
- Thrives in moist, well-drained, calcareous soils
- Frequent in swamps, stream edges, bogs, limestone outcrops
- Shade tolerant; often establishes in the understory or at forest edges
Landscape Uses of Northern White Cedar
Highly valued for both functional and aesthetic purposes, arborvitae is a popular choice in managed landscapes.
- Hedges & Windbreaks: Dense foliage makes it ideal for privacy screens, wind barriers, and living fences
- Specimen Trees: Many cultivated varieties offer ornamental appeal for parks, gardens, and cemetery plantings
- Wildlife Habitat: Provides shelter and food for birds (especially in winter), small mammals, and deer
- Soil Stabilization: Suitable for preventing soil erosion, especially in wet areas
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Wood and Traditional Uses
The wood of Northern White Cedar is light, soft, yet remarkably durable—especially in contact with ground and moisture. Despite its low strength for structural use, it possesses several highly practical applications:
- Construction: Fence posts, rustic poles, siding, rot-resistant lumber for docks and outdoor structures
- Shingles and Shakes: Traditional material for weather-resistant roof and wall coverings
- Crafts: Canoe ribs, boxes, specialty woodwork
- Medicinal: Indigenous peoples used bark and leaves for teas, decoctions, and poultices
Cultivars and Artificial Selections
Over centuries, horticulturists have bred many ornamental cultivars of Northern White Cedar:
- Varieties range in color (from yellow to rich green), growth habit (columnar, globular, dwarf), and cone production
- Selected for tolerance to varied soils, pest resistance, and landscape value
- Popular arborvitae types in gardens are almost always Northern White Cedar derivatives
Wildlife Value and Ecological Importance
Northern White Cedar supports remarkable wildlife diversity, especially in winter when many other resources are scarce. Its dense foliage and seed-filled cones offer food and protection for a variety of species.
- Deer browse on foliage, especially in harsh winters
- Shelter for overwintering birds (like chickadees, sparrows, and thrushes)
- Seeds eaten by small mammals and birds
- Cedar swamps function as critical wetland habitats for amphibians and rare plants
How to Grow Northern White Cedar
Site Selection
Choose a sunny to partially shaded site with moist, well-drained soil for optimal growth. While adaptable to different pH levels, Northern White Cedar thrives best on calcareous (alkaline) soils.
- Full sun to partial shade
- Moist to moderately dry soil; avoid sites prone to drought stress during establishment
- Tolerates periodic flooding and road salt exposure
Planting Tips
- Dig a hole twice as wide as the rootball and as deep as its height
- Set the tree so the crown sits at or slightly above ground level
- Backfill with native soil, water thoroughly
- Mulch around base to retain moisture, but keep mulch away from the trunk
Maintenance and Care
- Water regularly, especially in the first year after planting
- Prune lightly to maintain shape or control size, ideally in late winter or early spring
- Fertilize sparingly; too much nitrogen can inhibit root development and reduce winter hardiness
- Monitor for common pests and root rot in overly wet or compacted soils
- In areas with heavy deer populations, consider protection from browsing
Common Threats and Problems
- Deer Browse: A primary threat; in many regions, cedar swamps become ‘browse lines’ where lower foliage is entirely stripped
- Pests & Diseases: Bagworms, spider mites, leafminers, root rot (in saturated soils), and canker diseases
- Wind & Snow Damage: Heavy snow can break branches; wind can topple trees with shallow roots in poorly drained sites
- Drought: Young trees are especially sensitive to drying out
Distinguishing Northern White Cedar from Similar Species
| Species | Key Differences |
|---|---|
| Eastern Redcedar (Juniperus virginiana) |
|
| Western Redcedar (Thuja plicata) |
|
Frequently Asked Questions (FAQs)
Q: How can I quickly distinguish Northern White Cedar from similar-looking conifers?
A: Look for flattened, fan-like sprays of scale-like leaves, reddish-brown shreddy bark, and small, yellowish-brown woody cones. Eastern Redcedar and Western Redcedar have different leaf shapes and cones.
Q: Is Northern White Cedar good for privacy hedges?
A: Yes, its dense branching and year-round foliage make it popular for hedges, screens, and windbreaks alike.
Q: How long does Northern White Cedar live?
A: It is a long-lived species; natural stands can persist for hundreds of years, especially in protected, swampy habitats.
Q: What wildlife relies on Northern White Cedar?
A: Many birds use cedar for roosting and nesting, deer browse the foliage, and a variety of small mammals and birds feed on seeds.
Q: How can I protect my cedar trees from deer?
A: Fencing, repellents, and tree guards are effective. In large properties, promote natural predator habitats to help curb deer populations.
Conclusion
The Northern White Cedar remains a vital part of North America’s natural heritage and managed landscapes. Appreciated for its resilience, ecological value, and versatility, arborvitae is a valuable addition to gardens, parks, restoration projects, and wild spaces. With thoughtful identification, propagation, and care, Northern White Cedar continues to thrive amidst changing environmental conditions and human impact.
References
- https://www.dnr.state.mn.us/trees/northern-white-cedar.html
- https://growitbuildit.com/white-cedar-thuja-occidentalis/
- https://trees.umn.edu/northern-white-cedar-thuja-occidentalis
- https://plants.usda.gov/DocumentLibrary/plantguide/pdf/pg_thoc2.pdf
- https://bplant.org/compare/133-3347
- https://en.wikipedia.org/wiki/Thuja_occidentalis
- https://www.youtube.com/watch?v=68-2Jn_DYK4
- https://snr.unl.edu/data/trees/identification/basictree.aspx?sid=44
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