Thuja plicata, commonly known as Western Red Cedar, is a large evergreen tree native to the Pacific Northwest of North America. It can grow up to 70 meters tall and has a conical shape with dense foliage. The scale-like leaves are arranged in flattened sprays, giving the tree a feathery appearance. The bark is reddish-brown, fibrous, and marked by deep furrows. The Western Red Cedar is a vital species in the region's ecosystem, providing habitat for various wildlife such as birds, squirrels, and deer. It also holds cultural significance for indigenous communities, who use it for traditional purposes like building canoes and crafting totem poles. Beyond its ecological importance, Thuja plicata has substantial commercial value due to its durable wood, which is commonly used in constructing outdoor structures such as decks and fences. Its essential oil is also prized in aromatherapy for its calming properties. However, Thuja plicata faces significant threats. Habitat loss from logging activities and climate change-induced droughts make it susceptible to diseases like root rot. In summary, Thuja plicata plays a crucial role both ecologically and culturally. Conservation efforts are essential to preserving this iconic species of North America's Pacific Northwest.
Western Red Cedar: In Canada and the United States, most authorities refer to the English name as "western red cedar," or sometimes as "western red-cedar," to clarify that it is not a true cedar (genus Cedrus). However, the texture of the wood produced by this plant is similar to that of Cedrus, and it is also reddish-brown.
Western red cedar is highly resistant to disease and is generally not prone to illnesses. Regarding care, this plant is fairly low-maintenance. When grown outdoors it needs only minimal watering, and larger plants typically do not require pruning. Smaller plants, however, should be pruned after they have bloomed. Western red cedar is suitable for anyone with an outdoor area, such as a garden or deck, and does not require much care experience.
How to keep Thuja Plicata.
Light
Western red cedar grows best in full, unobstructed sun but can also adapt to partial shade. Native to sunny areas, it performs well through the different stages of growth. However, too much or too little sun can negatively affect its optimal growth and health.
Water
Western red cedar, which naturally grows in moist forests, flourishes in consistently humid conditions and favors evenly moist soil. To avoid root saturation, water the plant every 1-2 weeks. As an evergreen, its dense foliage helps retain water, reducing transpiration and conserving moisture.
Temperature
The natural growing conditions for western red cedar call for temperatures between 5 and 35 ℃ (41 to 95 ℉). Inside that span, the tree prefers cooler conditions and, with proper winter protection, can endure winter lows down to -40 ℃ (-40 ℉). In summer, providing shade and keeping the soil consistently moist is advised to avoid heat stress.
Fertilizer
Western red cedar has specific nutrient needs and does not require heavy fertilization. Fertilizing in spring is the best time for encouraging optimal growth. Providing nutrients enhances its health, raises its resistance to pests and diseases, and helps sustain its long lifespan.
Pruning
Prune Western red cedar, which is known for its aromatic leaves and conical shape, between early and late winter. Focus on removing any dead or diseased branches while avoiding heavy cutting to minimize stress on the tree. Proper pruning promotes better air circulation, reduces the risk of disease, and helps maintain the tree's visual appeal. Always use clean, sharp tools for the best results.
Botanical profile.
- Plant Type
- Tree
- Life Cycle
- Perennial
- Genus
- Thuja
- Family
- Cupressaceae
- Hardiness Zone
- 5-9
- Mature Height
- 64.92 m to 70.1 m
- Mature Spread
- 4.57 m to 6.1 m
- Leaf Color
- Green, Yellow, Variegated
- Leaf Type
- Evergreen
- Flower Color
- Yellow, Green, Black
- Flower Size
- 0.10 cm to 0.25 cm
- Bloom Time
- Early spring, Mid spring
- Planting Time
- Spring, Autumn
- Harvest Time
- Mid summer, Late summer, Early fall
Other names.
Reader questions.
How should I water my Western red cedar?
Watering your Western red cedar is a simple task that can be done using a garden hose. For mature trees, a high volume of water may be needed, so using a garden hose is ideal. However, for smaller trees, a watering can or smaller tool can suffice. It is important to avoid overhead watering, as excessive moisture on the leaves can lead to disease, especially for young trees.
Why is it important to add fertilizer to my Western red cedar plant?
To promote healthy growth in Western red cedar, make sure to fertilize it in the spring. Since this plant has a long lifespan, it requires support. Adding nutrients to the soil not only enhances its health but also boosts its resistance against pests and diseases that can hinder growth or reduce its lifespan.
What are the sunlight requirements for Western red cedar?
Western red cedar thrives under full, unobstructed solar exposure but can also adapt to a partially shaded environment. It originates from locations abundant in solar light, managing well through varying stages of development. However, excessive or insufficient sun can affect its optimal growth and overall health.
What is the native growth environment of Western red cedar?
The native growth environment of Western red cedar (Thuja plicata) requires a temperature range of 5 to 35°C (41 to 95°F). This species thrives in cooler temperatures and can tolerate winter lows down to -40°C (-40°F) with adequate protection. It is recommended to provide shaded areas and consistent moisture during hotter months to prevent heat stress. Western red cedar shows a strong resistance to cold, making special frost protection measures unnecessary in winters, except when temperatures are expected to plummet below -25°C. In such cases, protecting the trunk and branches with materials like non-woven fabric can be beneficial. Moreover, watering the plant abundantly before the first freeze in autumn to ensure the soil remains moist is advised to help the plant through winter.
What should I do if I give my Western red cedar too much or too little water?
Overwatering can happen when the soil doesn't allow water to drain properly, causing the Western red cedar to deteriorate. If this is the case, you can improve drainage by amending the soil or finding a better location for your plant. If you're growing the cedar in a pot, you may need to repot it with looser soil and a container that allows for better drainage. Overwatering can also lead to diseases, which should be treated promptly. On the other hand, if your cedar is underwatered, simply increase watering frequency to help it recover. You can determine if you've overwatered by examining the foliage, particularly the new growth, for signs of discoloration or easy breakage. If you see standing water or slow drainage in the plant's area, it indicates excessive moisture in the soil. Underwatered cedars will have sparse, brown leaves. Consider recent rainfall or high temperatures if you notice such symptoms, as they can help you make the correct assessment.
When should I put fertilizer on my Western red cedar?
The growing medium may not always provide sufficient nutrients for healthy growth, but Western red cedar is unique compared to garden plants. It doesn't need a lot of extra nutrients. For this specific type of cedar, the ideal time to fertilize is in the spring, before new growth emerges.
How does artificial lighting benefit indoor plants?
Indoor plants require adequate lighting for optimal growth. When natural sunlight is insufficient, especially in winter or less sunny spaces, artificial lights provide a crucial alternative. LED lights are popular for indoor plants because they offer specific wavelengths needed by plants. Full sun plants need 30-50W/sq ft, partial sun plants 20-30W/sq ft, and full shade plants 10-20W/sq ft of artificial light. The light source should be placed 12-36 inches above the plant to mimic natural sunlight, and most plants need 8-12 hours of light per day.
How does low temperature affect Western red cedar and what should be done?
Western red cedar is cold-tolerant, thriving best above 5°C and ideally kept above -20°C during winter. However, when temperatures fall below -25°C, there might not be noticeable changes during winter, but come spring, the branches may turn brittle and dry, and no new shoots will emerge. To combat this, it is advisable to prune away any dead branches in spring that have failed to produce new leaves, aiding in the recovery and health of the plant.
How many times a week should I water my Western red cedar?
A mature Western red cedar tree is quite low-maintenance when it comes to watering. It typically survives just fine on rainfall alone, becoming drought tolerant. During the hottest months, a weekly watering is sufficient, but for the rest of the year, watering may not be necessary. The only exception is if the tree has recently been planted, in which case regular watering is important to help establish the roots. However, one key point to remember is that standing water is not tolerated by this species. So, if you're unsure, it's better to avoid watering the tree too much rather than risking overwatering it.
When is it not a good idea to add fertilizer to my Western red cedar?
Western red cedar has different fertilizer needs compared to other plants. It does not require frequent fertilization like some plants do. In fact, too much fertilizer can harm it, causing it to die back. It's best to only apply fertilizer in the spring and avoid doing so during the summer, fall, and winter. During these seasons, refrain from adding any fertilizer or organic matter to the soil for the cedar.
What are the symptoms of light deficiency in Western red cedar?
When exposed to suboptimal lighting, Western red cedar may present symptoms like smaller new leaves, leggy or sparse growth, faster leaf drop, halted growth, and lighter-colored or irregularly patterned new leaves. These indicate a struggle with inadequate sunlight exposure.
How does high temperature affect Western red cedar and what is the recommended care?
In high temperatures, particularly above 35°C, Western red cedar may exhibit signs of stress such as lighter leaf color, dry and withered tips, and increased susceptibility to sunburn. To remedy this, trim away any sunburned and dried-up parts of the plant. Moving the plant to a shaded location or using shade cloth to protect it from midday and afternoon sun can also help. Ensuring the soil remains moist by watering in the morning and evening will further support the plant's health during hot periods.
