← Plant Guides

How to Grow Western Red Cedar 'Techny's Emerald'

Wikimedia Commons

Western Red Cedar 'Techny's Emerald'

Thuja plicata 'Techny's Emerald'

tree

'Techny's Emerald' is a narrow, columnar cultivar of Western Red Cedar prized for its dense, vibrant emerald-green foliage and compact growth habit. It reaches 40-50 feet tall but only 8-12 feet wide, making it ideal for screening, windbreaks, and small-space landscaping. This cold-hardy variety maintains its rich color through winter and performs well in northern climates.

When should you plant Western Red Cedar 'Techny's Emerald' in your zone?

Get a personalized planting timeline — when to start seeds, transplant, and harvest — based on your USDA zone and local frost dates. Free to start.

Get my Western Red Cedar 'Techny's Emerald' timeline →

Example Western Red Cedar 'Techny's Emerald' timeline · Pittsburgh, PA (Zone 6b)

  1. Plant Western Red Cedar 'Techny's Emerald'

    Around Apr 17

    Near Pittsburgh's average last spring frost.

  2. Tend & protect

    Late spring–summer

    Watering, feeding, and pest-watch reminders.

  3. Harvest Western Red Cedar 'Techny's Emerald'

    Late summer into fall

    Before the first fall frost (≈ Nov 8)

Sample dates for Pittsburgh, PA. Sign up to get exact Western Red Cedar 'Techny's Emerald' dates for your own zip code.

Growing Conditions

☀️
Sun: Full sun to partial shade; needs at least 4-6 hours of direct sunlight for best color density
💧
Water: Moderate watering; keep soil consistently moist during establishment (first 2 years). Once established, fairly drought-tolerant but prefers regular moisture. Avoid waterlogging.
📏
Spacing: 36-60 inches (3-5 feet) for screening plantings; single specimens need 5-6 feet minimum clearance from structures inches
📅
Days to maturity: Trees do not have traditional maturity; reaches mature shape in 8-12 years
🌱
Planting depth: Plant at the same depth as the root ball; do not bury the crown

Soil

Type: Well-draining loamy or slightly moist soil; tolerates clay and poor soils
pH: 5.5-7.0
Amendments:
Compost or aged bark mulch Peat moss for moisture retention Coarse sand if drainage is poor

Growing Zones

Find your zone →

Zones 3-8; exceptionally winter-hardy for a Western Red Cedar cultivar

3a 3b 4a 4b 5a 5b 6a 6b 7a 7b 8a

Sign up free to see if Western Red Cedar 'Techny's Emerald' grows in your zone — and get a personalized planting timeline.

Get my Western Red Cedar 'Techny's Emerald' timeline →

Growth Stages

1

Establishment (Year 1)

3-6 months

Small transplant developing root system; foliage may appear slightly stressed or bronze-tinted initially

Water deeply 2-3 times weekly; provide windbreak protection in exposed locations; mulch base with 2-3 inches of bark; avoid fertilizing in first year

2

Young Growth (Years 2-3)

24 months

Rapidly filling in with dense, columnar form; foliage transitions to full emerald color; visible height and width increase annually

Reduce watering frequency as roots deepen; light pruning to shape as needed; apply balanced fertilizer in early spring if growth appears slow

3

Maturing (Years 4-8)

48 months

Tree approaches full height and width; branching becomes dense throughout; full vibrant emerald color achieved; minimal new growth rate

Water during droughts only; minimal pruning unless shaping for windbreak; no fertilizer needed if soil adequate

4

Mature Form (Year 8+)

Indefinite (long-lived, 50+ years)

Fully established columnar tree; 40-50 feet tall, 8-12 feet wide; dense foliage from ground to apex; winter color stable

Occasional pruning for dead wood or size control; no supplemental water except extreme drought; monitor for spider mites in dry climates

Companion Planting

Plan your garden →

Plant with:

Boxwood (low-growing backdrop) Juniper varieties (similar conifer aesthetic) Serviceberry (seasonal interest complement) Dwarf Hinoki Cypress (textural contrast) Viburnum (underplanting shrub)

Avoid planting near:

Black Walnut (juglone toxicity) Salt-spray areas (coastal salt damage) Poorly drained sites (root rot risk) Areas with heavy foot traffic (branch breakage from disturbance)

Common Pests

  • Spray foliage with water to dislodge; use insecticidal soap or horticultural oil in severe cases; increase humidity; more common in hot, dry climates

  • Prune and remove infested branch tips; apply insecticide at bud break in spring; generally minor in northern zones

  • Install deer fencing (6+ feet height); apply deer repellent sprays; plant in protected locations

  • Ensure excellent drainage; avoid overwatering; improve soil drainage with amendments; remove severely affected trees

Uses

🏠

Windbreak and Privacy Screening

Household

'Techny's Emerald' is widely used to create effective windbreaks and visual privacy screens due to its tall, narrow form and dense branching. A single row or staggered planting provides year-round screening and wind protection for properties and gardens. [source]

🦋

Bird and Small Animal Shelter

Wildlife

The dense, fine-textured foliage provides excellent cover and nesting sites for songbirds and small mammals. The tree serves as a refuge from predators and harsh weather throughout the year. [source]

🎨

Floral Design and Greenery

Craft

Branches are harvested for fresh and dried floral arrangements, wreaths, and holiday decorations. The foliage has a pleasant, distinctive cedar aroma. [source]

🏠

Ornamental Landscaping

Household

'Techny's Emerald' is a premier choice for formal gardens, contemporary landscapes, and small properties where a tall accent plant is needed without excessive width. The columnar shape complements modern architecture and provides year-round visual interest. [source]

💊

Traditional Thuja Remedies

Medicinal

Western Red Cedar has been used in traditional Indigenous medicine and herbalism for respiratory support and immune function. The aromatic oil contains thujone and other compounds with historical medicinal applications. [source]

This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.

Harvest Tips

This is an ornamental tree; no traditional harvest. Prune branches for greenery arrangements or wreaths in late fall/early winter. Remove dead wood anytime. Light shaping can be done in early spring or late summer to maintain columnar form.

Fun Facts

  • 🌱 'Techny's Emerald' was specifically selected for winter hardiness at the Chicago Botanic Garden (formerly Tecny Nursery), making it one of the most cold-hardy Western Red Cedar cultivars available and suitable for USDA zone 3 gardens where standard selections would fail.
  • 🌱 Western Red Cedar is not a true cedar (Cedrus genus) but a member of the cypress family; its wood is naturally rot-resistant and contains compounds (thujone, cedrol) that inhibit decay, which is why it has been prized for roofing shingles and outdoor structures for centuries.
  • 🌱 The narrow columnar form can reach 40-50 feet tall but only 8-12 feet wide, making it one of the narrowest tall conifers available and capable of fitting into spaces where traditional shade trees or broader screening plants cannot.

Gardening Terms

New to gardening? Learn about terms used in this guide:

Annual Cultivar Full Sun Mulch Partial Shade Transplant
Shop Western Red Cedar 'Techny's Emerald' plants and related plants at Plant Addicts →

Join 30,000 gardeners planning their gardens with LizPlants.

Get your personalized Western Red Cedar 'Techny's Emerald' planting timeline

Tell us your zip code and we'll calculate exactly when to start Western Red Cedar 'Techny's Emerald' seeds, transplant seedlings, and harvest — based on your USDA zone and local frost dates. Includes calendar reminders and printable task lists. Free to start.

Get my Western Red Cedar 'Techny's Emerald' timeline →