Northern White Cedar
thuja occidentalis
Also known as: ["Arborvitae","White Cedar","Eastern Arborvitae"]
Overview
A coniferous evergreen tree native to North America, valued for its dense foliage and ornamental uses.
Benefits & Perks
["disease resistant","cold hardy","wildlife attractant (bees, butterflies, birds)","shade tolerant"]
Botanical Classification
| Phylum: | Pinophyta |
| Class: | Pinopsida |
| Order: | Pinales |
| Family: | Cupressaceae |
| Genus: | Thuja |
| Botanical Name: | Thuja occidentalis |
Plant Characteristics
Basic Information
- Category: Trees
- Suitable Location: outdoor garden bed or container in a sheltered spot
- Suitable For:
- Is Weed: No
- Allergenicity: low
Environmental Needs
- Climate: {"temperatureRange":"–30–40°C"}
- Hardiness: {"zones":"3–7"}
- Misting: rarely required, only if indoor air is very dry
- Drainage: Moderately well-draining to well-draining.
- Soil Type: Well-draining, loamy soil with organic matter.
Maintenance Level
- Maintenance Level: moderate
- Toughness Level: high
- Pruning Frequency: Annually in late winter or early spring before new growth begins.
- Pruning Intensity: Moderate; remove up to one-third of old growth if needed.
Care Details
Ideal Sunlight Coverage:
Full sun to partial shade (4–6 hours of direct sunlight daily). Adjust for intense summer sun by providing afternoon shade.
Sunlight Tolerance Tips:
Acclimate plants gradually to direct sunlight to prevent scorching. For indoor placement, use a south-facing window with sheer curtains.
Care Requirements
Care Difficulty
easymoderate
Sunlight
full sun to partial shade
Rotate plant for even growth; use shade cloth in extreme heat; avoid direct midday sun in summer.
Watering
every 7–10 days, allowing soil to dry slightly between waterings
Water thoroughly until runoff, allow soil to dry slightly between waterings, and avoid waterlogging.
Soil
well-drained, loamy soil with moderate organic content
pH: Acidic to slightly alkaline (pH 5.5–7.0).
Avoid heavy clay soils; ensure good drainage; amend with organic matter for fertility.
Temperature
Hardy in USDA zones 2–7; tolerates temperatures from -40°F to 90°F. Prefers cool roots and moderate air temperatures.
Protect from frost in early spring; avoid placing near heat sources; maintain consistent temperatures.
Fertilizing
every 4–6 weeks during spring and summer with balanced liquid fertilizer
Fertilize only when actively growing; avoid over-fertilization; water before and after feeding.
Propagation
Methods
Stem cuttings taken in late spring or early summer.
Step-by-Step Propagation Guide
- Take 4–6 inch cuttings.
- Remove lower leaves.
- Dip in rooting hormone.
- Plant in medium.
- Maintain humidity.
Best Time: Late spring to early summer when new growth is firm but not woody.
Environment
High humidity (70–90%), indirect light, and consistent warmth (65–75°F).
Medium
Peat-based mix with perlite or sand for good drainage.
Hormone
Rooting hormone is recommended for faster and more reliable rooting.
Timeline
Roots typically form in 4–8 weeks; establish in new pot after 3–6 months.
Tools Needed
Pruning shears, rooting hormone, propagation tray, humidity dome, misting bottle.
Quick Tips
Use healthy, non-flowering stems; maintain consistent moisture; avoid direct sunlight.
Pruning & Repotting
Pruning Guide
Method
Selective thinning and heading back to maintain form and health.
Pruning Plan
Shape the plant, remove dead or diseased branches, and encourage denser growth.
Tools
Pruning shears, loppers, gloves, disinfectant.
Checklist
Disinfect tools; prune dead/diseased wood first; make clean cuts; avoid over-pruning.
Repotting Guide
Best Season
Early spring before active growth starts.
Pot Size
Increase pot size by 2–3 inches in diameter.
Method
Remove plant gently; trim roots if necessary; place in new pot with fresh soil; water thoroughly.
Suggestions
Repot every 2–3 years or when roots fill the container. Necessary to refresh soil and provide space.
Checklist
Check root bound status; prepare new pot; use fresh soil mix; water after repotting.
Advanced Care Tips
Watering Mastery
Watering Checklist
Check soil moisture; water deeply; ensure drainage; avoid wetting foliage.
How to Apply Water Properly
Water at the base of the plant, ensuring moisture reaches the root zone. Water early in the morning to minimize evaporation and allow foliage to dry.
Watering Schedule Tips
Water deeply once a week during spring and summer, reducing frequency to every 2–3 weeks in fall and winter. Adjust based on rainfall and soil moisture.
Soil Improvement
Add compost or peat moss for fertility; mix perlite or sand for drainage; ensure good aeration.
Temperature Stress Management
Signs of Temperature Issues
Wilting, browning foliage, needle drop, or stunted growth.
Cold Stress
Leaves may turn brown or purple; growth slows or halts; potential dieback in severe cases.
Solution: Mulch heavily around the base; protect from harsh winds; avoid overwatering in cold weather.
Hot Stress
Wilting, leaf scorch, reduced growth, or needle drop due to excessive heat and dryness.
Solution: Provide shade during peak heat; increase watering frequency; use mulch to retain soil moisture.
Fertilizing Guide
Fertilizing Checklist
Check growth stage; use appropriate fertilizer; apply at recommended rates; water after fertilizing.
Fertilizing Method
Use a balanced, slow-release fertilizer in early spring. Dilute liquid fertilizer to half-strength if needed. Avoid fertilizing in late fall or winter.
Common Problems & Solutions
Toxicity Warning
Cats
Slightly ToxicCats are sensitive to thujone and may experience mild gastrointestinal upset or mild neurological symptoms if they ingest Thuja occidentalis. The effects are typically not severe but warrant attention.
⚠️ Symptoms:
🌿 Toxic Parts:
⚡ Toxic If:
if eaten
Dogs
Slightly ToxicIn dogs, ingestion of Thuja occidentalis can lead to mild gastrointestinal upset due to the presence of thujone. While generally not life-threatening, ingestion should be avoided to prevent discomfort.
⚠️ Symptoms:
🌿 Toxic Parts:
⚡ Toxic If:
if eaten
Humans
Slightly ToxicThuja occidentalis contains thujone, a compound that can cause mild gastrointestinal distress and central nervous system effects when ingested in significant quantities. The physiological impact is generally limited to mild irritation and discomfort.
⚠️ Symptoms:
🌿 Toxic Parts:
⚡ Toxic If:
if eaten
Frequently Asked Questions
Q: Is Thuja occidentalis suitable for hedges?
A: Yes, it is commonly used for hedges due to its dense growth habit and tolerance to pruning.
Q: How fast does Thuja occidentalis grow?
A: It grows at a moderate rate, typically 12-24 inches per year under optimal conditions.
Q: Does Thuja occidentalis require full sun?
A: It prefers full sun but can tolerate partial shade, especially in hotter climates.
Quick Reference
| Family: | Cupressaceae |
| Care: | easy |
| Light: | full sun to partial shade |
| Water: | every 7–10 days, allowing so |
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