How to Grow Thuja Green Giant
Thuja Green Giant
Thuja × 'Green Giant'
treeThuja Green Giant is a vigorous, fast-growing evergreen conifer that is a hybrid cross between Western Arborvitae and Japanese Arborvitae. It's prized as a privacy screen and windbreak due to its columnar shape, dense foliage, and rapid growth rate of 3-4 feet per year. The bright green, soft-textured foliage remains vibrant year-round and turns bronze-tinged during cold winters.
When should you plant Thuja Green Giant in your zone?
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Example Thuja Green Giant timeline · Pittsburgh, PA (Zone 6b)
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Plant Thuja Green Giant
Around Apr 17Near Pittsburgh's average last spring frost.
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Tend & protect
Late spring–summerWatering, feeding, and pest-watch reminders.
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Harvest Thuja Green Giant
Late summer into fallBefore the first fall frost (≈ Nov 8)
Sample dates for Pittsburgh, PA. Sign up to get exact Thuja Green Giant dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in zones 3b-8; tolerates zone 9 but may struggle in extreme heat without afternoon shade
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Get my Thuja Green Giant timeline →Growth Stages
Establishment
First 6-12 monthsYoung transplants with thin main stem and sparse branching; foliage is bright light green.
Water deeply 2-3 times weekly; apply 2-3 inches of mulch around base; stake tall transplants in windy sites; avoid heavy fertilization.
Vigorous Growth
Year 2-4Rapid vertical and lateral expansion; stem thickens, branching becomes denser, foliage develops full green color.
Maintain consistent moisture; apply balanced slow-release fertilizer in spring; allow natural columnar shape to form with minimal pruning; monitor for spider mites in dry conditions.
Full Screen Development
Year 3-5Dense, full columnar form reaches desired screening height; foliage fills in completely from ground to tip.
Light spring pruning for shape if desired; continue regular watering during droughts; apply single annual fertilization in early spring.
Mature
Year 5 onwards (indefinite)Established, full-size tree with dense green foliage; may reach 40-60 feet tall and 12-20 feet wide depending on age and conditions.
Water during extended dry periods; minimal pruning needed; monitor for winter damage or brown patches; prune selectively to maintain shape.
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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Spray foliage with water to dislodge mites; apply neem oil or miticide if populations are high; maintain consistent moisture to reduce stress
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Prune and remove affected foliage; apply spinosad or insecticidal soap in spring when larvae are active; maintain tree vigor
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Hand-pick and destroy egg cases in fall and winter; apply Bt (Bacillus thuringiensis) in late spring; use pheromone traps
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and
(Phytophthora, Armillaria)
Ensure well-draining soil; avoid overwatering; remove infected tissue; apply fungicide if caught early; replant in well-draining location
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Install deer fencing (7-8 feet tall); apply deer repellent sprays; plant in groups for better protection
Uses
Privacy screening and windbreak
HouseholdThuja Green Giant is widely used as a fast-growing privacy hedge, living fence, and windbreak due to its columnar form, dense foliage, and rapid growth rate of 3-4 feet annually. It effectively blocks sightlines and reduces wind within 3-5 years. [source]
Wildlife shelter and nesting habitat
WildlifeThe dense evergreen branches provide year-round shelter and nesting habitat for birds and small mammals. Songbirds particularly favor the protected interior spaces created by the columnar growth form. [source]
Decorative greenery
CraftFresh or dried branches of Thuja Green Giant can be used in seasonal floral arrangements, wreaths, and holiday decorations. The soft, feathery foliage is aromatic when brushed or crushed. [source]
Noise reduction
HouseholdDense conifer screens effectively dampen sound transmission, making them valuable for reducing traffic noise, neighborhood sounds, and other unwanted acoustic intrusion around residential properties. [source]
Traditional herbal use
MedicinalArborvitae species have a long history in traditional medicine and herbalism, though modern scientific evidence is limited. Some herbalists use thuja foliage for immune support, though proper safety assessment is essential before any internal use. [source]
This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.
Harvest Tips
Thuja Green Giant is not harvested for fruit or foliage for consumption. Small amounts of branches can be pruned for fresh or dried decorative greenery; prune lightly in spring to maintain form. No traditional 'harvest' applies to this ornamental screening tree.
Fun Facts
- 🌱 Thuja Green Giant grows so rapidly (3-4 feet per year) that it can create a full privacy screen in 5-7 years, making it one of the fastest-growing evergreen screening options available.
- 🌱 The hybrid origin of Thuja Green Giant (Western × Japanese Arborvitae) gives it superior vigor and hardiness compared to either parent species, a phenomenon called 'hybrid vigor.'
- 🌱 Thuja foliage contains thujaplicin, a naturally antimicrobial compound that helps protect the tree from fungal and bacterial pathogens, which is why the wood is aromatic and historically used for cedar products.
Gardening Terms
New to gardening? Learn about terms used in this guide:
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