How to Grow Emerald Arborvitae

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Emerald Arborvitae

Thuja occidentalis 'Emerald' (Thuja occidentalis 'Smaragd')

shrub

Emerald Arborvitae is a narrow, columnar evergreen shrub with vibrant green foliage that remains color-rich even in winter. It grows in a tight, pencil-like form making it ideal for hedges, windbreaks, and privacy screens. This cultivar is a superior selection of Eastern Arborvitae, prized for its uniform shape and disease resistance.

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Example Emerald Arborvitae timeline · Pittsburgh, PA (Zone 6b)

  1. Plant Emerald Arborvitae

    Around Apr 17

    Near Pittsburgh's average last spring frost.

  2. Tend & protect

    Late spring–summer

    Watering, feeding, and pest-watch reminders.

  3. Harvest Emerald Arborvitae

    Late summer into fall

    Before the first fall frost (≈ Nov 8)

Sample dates for Pittsburgh, PA. Sign up to get exact Emerald Arborvitae dates for your own zip code.

Growing Conditions

☀️
Sun: Full sun, 6+ hours daily; tolerates partial shade but foliage color and density are best in full sun
💧
Water: Moderate water needs; keep soil consistently moist but not waterlogged during establishment (first 2 years). Once established, fairly drought-tolerant but performs best with regular watering during dry spells. Water at soil level to reduce disease risk.
📏
Spacing: 24-36 inches
📅
Days to maturity: Matures fully over 15-20 years; reaches ornamental size in 5-8 years
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Planting depth: Plant at same depth as root ball; do not plant deeper than original nursery pot

Soil

Type: Well-draining loamy soil; tolerates clay and sandy soils
pH: 6.0-8.0
Amendments:
Compost at planting Peat moss for moisture retention Perlite for heavy clay soils

Growing Zones

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Thrives in zones 2-8, with best performance in zones 3-7

2a 2b 3a 3b 4a 4b 5a 5b 6a 6b 7a 7b 8a

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Growth Stages

1

Establishment

3-6 months

Young plants settling after transplanting; initial root development

Water deeply 2-3 times weekly for first season; mulch around base (2-3 inches) keeping away from trunk; avoid fertilizer first year to prevent tender growth

2

Vegetative Growth

1-3 years

Rapid vertical and lateral branching; densifying foliage in classic columnar form

Prune lightly only to maintain shape; avoid heavy heading cuts; apply light fertilizer in spring; continue consistent watering; monitor for spider mites in hot, dry conditions

3

Hedge Development

3-8 years

Plant reaches desired height and width for screening or hedge use; dense branching throughout

Annual light pruning in spring or early summer to maintain columnar form; hedge shears work well for formal shaping; fertilize annually in spring with balanced slow-release fertilizer

4

Mature Specimen

8+ years (long-lived)

Full-sized plant with dense, deep green foliage; reaches ultimate height of 12-20 feet and width of 3-4 feet

Minimal pruning needed; remove any dead or diseased branches; maintain mulch layer; water during prolonged droughts; monitor for winter damage or deer rubbing

Companion Planting

Plan your garden →

Plant with:

Avoid planting near:

Black walnut (Juglans nigra) Hackberry Sweet gum

Common Pests

  • Spray with strong water jet to remove webbing; use miticide if severe; increase humidity to discourage; avoid over-fertilizing with nitrogen

  • Hand-pick bags in fall/winter; spray with Bacillus thuringiensis (Bt) in early summer; use dormant oil spray before growth begins

  • Prune and destroy infested branch tips; spray with neem oil or horticultural oil in early spring; maintain plant vigor with proper care

  • and

    Install 7-8 foot tall fencing; apply deer repellent sprays; use motion-activated sprinklers; select resistant varieties (Emerald is relatively deer-resistant)

  • Ensure excellent drainage; avoid overwatering; space plants for air circulation; do not plant in poorly drained areas; improve soil with sand or perlite

Uses

🏠

Privacy Screening & Windbreaks

Household

The columnar form and dense foliage make Emerald Arborvitae ideal for creating tall, narrow privacy screens and windbreaks in residential landscapes. Requires minimal width (3-4 feet) while reaching 12-20 feet tall, efficiently blocking views and wind. [source]

🎨

Fresh Greenery & Holiday Arrangements

Craft

Fresh branches are prized in floral arrangements, wreaths, and holiday decorations for their vibrant green color and pleasant aromatic foliage. The branches hold well in water and maintain their color throughout the season. [source]

🏠

Formal Hedge & Topiary

Household

The naturally tight, columnar form responds well to formal pruning, making it suitable for creating structured hedges and geometric topiary shapes. Regular annual pruning maintains crisp lines and dense foliage. [source]

🦋

Wildlife Shelter & Nesting Habitat

Wildlife

Dense branching provides excellent shelter and nesting sites for small birds and beneficial wildlife. The evergreen foliage offers year-round cover and protection from predators. [source]

💊

Traditional Herbal Uses

Medicinal

Thuja species have been used in traditional medicine and herbal preparations, though internal use requires caution due to potential toxicity. Modern herbalists may use it in small quantities for respiratory support, though scientific evidence is limited. [source]

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

Harvest Tips

Emerald Arborvitae is not harvested for crop. Branches may be cut for fresh evergreen arrangements or wreaths in late fall/winter. Cut healthy branches with clean pruners, making cuts near branch junctions. Can be lightly pruned annually to maintain shape, but avoid cutting into dead wood as regrowth is slow.

Fun Facts

  • 🌱 Emerald Arborvitae (Smaragd) was selected in Denmark and introduced to North America in the 1950s; 'Emerald' and 'Smaragd' are the same cultivar—the names differ by region and marketing.
  • 🌱 The name 'arborvitae' means 'tree of life' in Latin, given because early European explorers believed it had medicinal properties for treating scurvy during long voyages.
  • 🌱 Emerald Arborvitae retains its vibrant green color in winter unlike some other Thuja cultivars, making it one of the few evergreens that doesn't bronze in cold weather.

Gardening Terms

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

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