Western Redcedar
Thuja plicata · Western Red-cedar · Giant Arbor-vitae · Pacific Red-cedar · Shinglewood · Western Or Giant Arborvitae · Western Red Cedar · Giant Cedar · Canoe CedarUSDA | Grow Zone
5-7Outdoors all year in zones 5 to 7. Anywhere colder, keep it as a houseplant.
- Light
- Full sun to partial shade
- Water
- Consistently moist soil
- Humidity
- Moderate to high humidity
- Temperature
- 20-80°F (-6-27°C)
- Difficulty
- Intermediate
- Growth
- Moderate
- Mature size
- 50-70 ft tall, 15-25 ft wide
Western Redcedar, known for its impressive height and aromatic wood, is a native tree to the Pacific Northwest. This majestic evergreen is valued for its durability and beauty, making it a popular choice for landscaping and timber.
Ask Vesper about Western Redcedar
Ideal temperature
20-80°F is where it grows fastest.
Spacing and harvest
- Mature size
- 50-70 ft tall, 15-25 ft wide
- Plant apart
- 180-300 in
- Frost
- Hardy: survives frost
Everything it needs
9 essentials at a glance
Watering
Western Redcedar prefers consistently moist soil, especially during its first few years of growth.
Water deeply once a week during dry spells, ensuring the soil remains damp but not soggy. Signs of over-watering include yellowing leaves and root rot, while under-watering may result in browning leaf tips and stunted growth.
Light
This tree thrives in full sun to partial shade, ideally receiving at least 6 hours of direct sunlight daily.
It can tolerate some shade but may grow more slowly and become less dense. For optimal growth, plant in a location where it can receive morning sun and some afternoon shade in hotter climates.
Soil
Western Redcedar prefers well-draining, loamy soil with a pH range of 6.0 to 7.5.
It benefits from a mix that includes organic matter to enhance drainage and moisture retention. Avoid heavy clay soils that can retain too much water and lead to root issues.
Humidity
This tree prefers moderate to high humidity levels, ideally above 40%.
To increase humidity, consider misting the foliage or placing a humidifier nearby. Signs of low humidity stress include browning leaf tips and increased susceptibility to pests.
Temperature
Western Redcedar thrives in temperatures ranging from 20°F to 80°F (-6°C to 27°C).
It is hardy in zones 5 to 7 and can tolerate cold winters. However, young trees may need protection from extreme heat and frost during their first few years.
Fertilizing
Use a balanced fertilizer with an NPK ratio of 10-10-10 or similar, applying in early spring and again in mid-summer.
Fertilize every 4-6 weeks during the growing season for best results. Signs of nutrient deficiency include yellowing leaves and poor growth.
Pruning
Prune Western Redcedar in late winter or early spring before new growth begins.
Use sharp, clean pruning shears to remove dead or damaged branches and to shape the tree. Regularly deadhead any spent flowers or seed cones to encourage new growth.
Repotting
Repot young trees every 2-3 years to provide fresh soil and space for growth.
Signs that repotting is needed include roots growing out of the drainage holes and stunted growth. When repotting, choose a pot that is 1-2 inches larger in diameter and ensure it has good drainage.
Propagation
Propagation can be achieved through seeds or cuttings.
For seeds, collect them in late summer, stratify for 30 days, and sow in spring. For cuttings, take 6-inch stem cuttings in late spring, dip in rooting hormone, and plant in a moist potting mix. Keep in a humid environment until roots develop, usually within 4-6 weeks.
When it's unhappy
Yellowing leaves
Why it happens
Often caused by over-watering or nutrient deficiencies.
How to fix it
Ensure proper drainage and adjust watering schedule. Consider applying a balanced fertilizer.
Browning leaf tips
Why it happens
Typically due to low humidity or under-watering.
How to fix it
Increase humidity around the plant and adjust watering frequency to keep soil consistently moist.
Root rot
Why it happens
Caused by overly wet soil and poor drainage.
How to fix it
Improve drainage and reduce watering frequency. If severe, consider repotting into fresh, well-draining soil.
Pest infestations (e.g., spider mites)
Why it happens
Dry conditions and lack of humidity can attract pests.
How to fix it
Increase humidity and use insecticidal soap or neem oil to treat infestations.
Fungal diseases
Why it happens
High humidity and poor air circulation can lead to fungal issues.
How to fix it
Ensure good air circulation around the plant and remove any affected foliage promptly.
Care through the year
Spring
In spring, apply a balanced fertilizer to promote healthy growth. Monitor for pests and prune any dead or damaged branches.
Summer
During summer, ensure consistent watering, especially during dry spells. Mulch around the base to retain moisture and regulate soil temperature.
Fall
In fall, reduce watering as growth slows. Clean up fallen leaves and debris to prevent fungal diseases and prepare the tree for winter.
Winter
In winter, protect young trees from extreme cold and frost. Consider wrapping the trunk with burlap if temperatures drop significantly.
Toxicity & Safety
Western Redcedar is considered non-toxic to pets and children. However, ingestion of large quantities may cause mild gastrointestinal upset. The wood can cause skin irritation in some individuals.
Good to know
How often should I water my Western Redcedar?
Water your Western Redcedar deeply once a week, especially during dry spells. Ensure the soil remains consistently moist but not soggy.
What type of soil is best for Western Redcedar?
Western Redcedar thrives in well-draining, loamy soil with a pH between 6.0 and 7.5. Adding organic matter can improve soil quality.
Can I grow Western Redcedar in a container?
Yes, Western Redcedar can be grown in a container, but ensure it is large enough to accommodate its root system and has good drainage.
Why are the leaves of my Western Redcedar turning yellow?
Yellowing leaves can indicate over-watering or nutrient deficiencies. Check your watering schedule and consider fertilizing if needed.
What pests affect Western Redcedar?
Common pests include spider mites and aphids. Regularly inspect your plant and use insecticidal soap or neem oil if pests are detected.
How tall does Western Redcedar grow?
Western Redcedar can reach heights of 50 to 70 feet and spread 15 to 25 feet wide, making it a significant addition to any landscape.
When is the best time to prune Western Redcedar?
The best time to prune Western Redcedar is in late winter or early spring, before new growth begins. This helps maintain its shape and health.
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