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How to Grow Smaragd Arborvitae

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Smaragd Arborvitae

Thuja occidentalis 'Smaragd'

shrub

Smaragd is a narrow, columnar evergreen cultivar of Eastern arborvitae prized for its compact, upright growth habit and vibrant emerald-green foliage year-round. It maintains a tight, dense form without frequent pruning and grows slowly to 15-20 feet tall with a width of only 3-4 feet. This popular ornamental is ideal for screening, windbreaks, and formal landscaping.

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

  1. Plant Smaragd 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 Smaragd Arborvitae

    Late summer into fall

    Before the first fall frost (≈ Nov 8)

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

Growing Conditions

☀️
Sun: Full sun to partial shade; requires minimum 4-6 hours of direct sunlight daily for best color
💧
Water: Moderate moisture needs; water deeply and regularly during establishment (first 2 years). Once established, tolerates drought well but prefers consistent moisture. Avoid waterlogging.
📏
Spacing: 36-48 inches
📅
Days to maturity: Not applicable; reaches mature ornamental form 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

Soil

Type: Well-draining loamy soil; tolerates clay and sandy soils
pH: 6.0-7.5
Amendments:
Compost Peat moss Sand for drainage improvement

Growing Zones

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Zones 3-8, 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

Transplant/Establishment

First year to 18 months

Young shrub with 1-2 feet of growth establishing roots in landscape. Foliage is bright green but plant is still developing structure.

Water deeply 2-3 times weekly. Mulch 2-3 inches around base (not touching trunk). Avoid pruning year 1. Monitor for wind damage in exposed sites.

2

Early Growth

Years 2-3

Plant grows 8-12 inches annually, forming a tight columnar shape. Foliage becomes denser and more vibrant green.

Continue regular watering during dry spells. Light pruning of damaged branches only. Remove competing weeds around base. Maintain mulch layer.

3

Development

Years 4-6

Shrub reaches 6-12 feet height, developing full columnar form. Color deepens to rich emerald green in full sun conditions.

Reduce watering frequency as root system matures. Prune only to remove dead branches or maintain shape. Apply balanced slow-release fertilizer in spring.

4

Maturity

Year 7 onward

Reaches maximum height of 15-20 feet with dense, uniform columnar form. Foliage displays deep emerald color year-round.

Minimal maintenance required. Water during extended droughts. In zone 2-3, wrap young plants in winter to prevent snow/ice damage. Remove any diseased branches promptly.

Companion Planting

Plan your garden →

Plant with:

Dwarf Alberta spruce Wintercreeper euonymus Boxwood Juniper Japanese yew Hydrangea

Avoid planting near:

Salt spray sources (very salt-sensitive) Poorly drained low spots Competitive tree roots

Common Pests

  • Spray foliage with water to increase humidity; apply miticide if severe. More common in hot, dry conditions.

  • Hand-pick bags in winter. Spray with Bt (Bacillus thuringiensis) in early summer when larvae are young.

  • Dormant oil spray in early spring; horticultural oil in growing season for active infestations.

  • and

    Strong water spray; neem oil or insecticidal soap if populations become heavy.

Uses

🏠

Privacy Screening & Windbreaks

Household

The narrow columnar form and dense foliage make Smaragd ideal for creating living privacy screens and windbreaks in residential landscapes. Plant in rows 3-4 feet apart to create continuous barriers. [source]

🏠

Formal Garden Accents

Household

The naturally tight, upright form requires minimal pruning, making Smaragd perfect for formal gardens, hedges, and architectural landscaping where geometric forms are desired. [source]

🦋

Wildlife Habitat

Wildlife

Dense arborvitae foliage provides shelter and nesting habitat for birds and small mammals. Foliage is also browsed by deer, though mature trees are less palatable. [source]

🏠

Year-Round Ornamental Color

Household

Smaragd maintains its vibrant emerald-green color throughout winter, providing reliable color contrast and structure in the landscape when deciduous plants are bare. [source]

Harvest Tips

Not applicable; this is an ornamental shrub grown for foliage. Prune only as needed in late winter or early spring to remove dead or diseased branches.

Fun Facts

  • 🌱 Smaragd (meaning 'emerald' in German) was selected for its superior winter color retention compared to standard arborvitae; many green cultivars brown or bronze in cold winters, but Smaragd stays emerald green.
  • 🌱 The cultivar was developed in Denmark and introduced to North America in the 1950s, and is now one of the most popular arborvitae varieties worldwide for screening and hedging.
  • 🌱 Thuja occidentalis wood has traditionally been used for fence posts, shingles, and canoe building due to its rot resistance; the essential oil has been used in traditional medicine and pest control.

Gardening Terms

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

Annual Cultivar Full Sun Mulch Partial Shade
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