How to Grow Green Giant Western Red Cedar

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Green Giant Western Red Cedar

Thuja plicata 'Green Giant'

tree

Green Giant is a fast-growing cultivar of Western Red Cedar that reaches impressive heights of 40-60 feet with a narrow, columnar form ideal for screening and windbreaks. It maintains a vibrant green color year-round and is remarkably hardy and disease-resistant. This evergreen conifer is one of the fastest-growing trees available, gaining 3-4 feet annually under ideal conditions.

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Example Green Giant Western Red Cedar timeline · Pittsburgh, PA (Zone 6b)

  1. Plant Green Giant Western Red Cedar

    Around Apr 17

    Near Pittsburgh's average last spring frost.

  2. Tend & protect

    Late spring–summer

    Watering, feeding, and pest-watch reminders.

  3. Harvest Green Giant Western Red Cedar

    Late summer into fall

    Before the first fall frost (≈ Nov 8)

Sample dates for Pittsburgh, PA. Sign up to get exact Green Giant Western Red Cedar dates for your own zip code.

Growing Conditions

☀️
Sun: Full sun to partial shade; 6+ hours of direct sunlight daily for best growth and color; tolerates light shade but grows denser in full sun
💧
Water: Moderate water needs once established; requires consistent moisture during first 2-3 years of growth; water deeply 1-2 times weekly during dry spells; drought-tolerant once established but prefers regular moisture; avoid waterlogged soil
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Spacing: 36 inches
📅
Days to maturity: Reaches maturity in 10-15 years; achieves landscape-ready height of 20-30 feet in 5-7 years
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Planting depth: Plant at same depth as root ball; top of root ball level with soil surface; do not bury stem

Soil

Type: Well-draining loamy to sandy soil; tolerates poor soil but prefers moderately fertile conditions
pH: 5.5-7.5
Amendments:
Compost or aged bark mulch at planting Peat moss for moisture retention in sandy soils Balanced slow-release fertilizer in spring

Growing Zones

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Thrives in zones 3-8; excellent cold hardiness and adapts well from northern to mid-Atlantic regions

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

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Growth Stages

1

Establishment

1-2 years

Young transplant establishing root system; relatively compact form; bright green foliage

Water regularly and deeply; apply 2-3 inches of mulch around base; avoid high-traffic areas; provide stakes if in windy location; fertilize monthly during growing season

2

Active Growth

3-7 years

Rapid annual growth of 3-4 feet; developing columnar shape; dense branching from ground to top

Continue consistent watering; mulch maintenance; light pruning only to remove dead branches; avoid heavy pruning which reduces density; monitor for spider mites in hot, dry areas

3

Maturation

5-10 years

Reaches desired height and fullness; dense foliage throughout; width of 15-20 feet

Reduce watering frequency; minimal pruning needed; prune only to maintain shape or remove dead wood; no fertilizer needed if soil is adequate

4

Landscape Integration

10+ years

Fully mature specimen providing excellent windbreak, screen, or backdrop; maintains vibrant green year-round

Occasional deep watering during extended drought; minimal maintenance; can remain in landscape for 50+ years with proper care

Companion Planting

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Plant with:

Avoid planting near:

Black Walnut (produces juglone toxin) Trees requiring very dry conditions (incompatible moisture needs) Plants sensitive to salt spray if used in coastal windbreaks

Common Pests

  • Spray with water to dislodge; use insecticidal soap or neem oil in severe infestations; provide adequate moisture to reduce stress

  • Hand-pick and destroy bags; apply Bacillus thuringiensis (Bt) in early summer when caterpillars are small

  • Prune infested branches; apply horticultural oil in early spring before growth begins

  • Spray with water; use insecticidal soap; natural predators usually control populations

Uses

🏠

Privacy Screening & Windbreak

Household

Green Giant's fast growth and dense columnar form make it ideal for creating living privacy screens and windbreaks. Plant in rows 6-8 feet apart to establish effective barriers within 3-5 years. [source]

🏠

Specimen Tree & Landscape Focal Point

Household

The narrow, pyramidal shape and vibrant evergreen color provide year-round visual interest as a specimen tree or backdrop for mixed borders. Excellent for creating vertical structure in residential landscapes. [source]

🦋

Wildlife Habitat & Bird Shelter

Wildlife

Dense foliage provides shelter and nesting sites for birds and small mammals. The tree offers food sources through seeds and attracts beneficial insects. [source]

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Sound & Wind Reduction

Household

When planted in rows, Green Giant effectively reduces wind speed and dampens outdoor noise pollution, making it valuable for properties near roads or in exposed areas. [source]

🏠

Low-Maintenance Tall Screening

Household

Once established, requires minimal pruning and maintenance while achieving heights of 40-60 feet, making it far easier than hedges or fence maintenance for tall privacy screens. [source]

Harvest Tips

Not applicable for timber harvest in residential settings; this is a landscape specimen tree. For arborists harvesting mature specimens, timing and technique depend on commercial timber objectives.

Fun Facts

  • 🌱 Green Giant can grow 3-4 feet per year, making it one of the fastest-growing narrow evergreen trees in North America; a 20-foot screen can be established in just 5-7 years.
  • 🌱 Western Red Cedar is naturally rot-resistant and was historically used by Pacific Northwest Native Americans for canoes, longhouses, and storage boxes; the 'plicata' in the scientific name refers to the distinctive flat, scale-like foliage.
  • 🌱 Despite its large mature size, Green Giant maintains a narrow form (15-20 feet wide) that makes it ideal for tight spaces where wide trees won't fit; it can be used as a living alternative to privacy fences on narrow properties.

Gardening Terms

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

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