Arborvitae (Thuja occidentalis)

Also known as: Tree of life, White-cedar

Northern white cedar (Thuja occidentalis) is a small- to medium-sized evergreen conifer native to North America, thriving in diverse habitats like forested wetlands and cliff sides. Its essential oils are valued in aromatherapy and natural insect repellents. Widely used in landscaping, it serves as an excellent choice for hedges, windbreaks, and ornamental purposes. With growing interest in its landscaping potential, smaller, compact varieties have been developed to suit various garden sizes and designs.

In This Article

Care Tips Water Sunlight Temperature Soil Fertilize Prune Propagation Repotting Toxicity

Attributes of Arborvitae

Lifespan

Perennial

Plant Type

Tree

Plant Height

15 m to 38 m

Spread

3 m to 4.5 m

Leaf Color

Green Yellow

Flower Size

1.3 cm

Flower Color

Yellow Green

Images of Arborvitae

Quickly Identify Arborvitae

Horizontal, layered branches distinguish arborvitae, reaching 10-15 feet (3-4.5 meters), potentially towering to 50 feet (15 meters).

0.4-0.5 inch (1-1.3 cm) oblong cones adorn arborvitae's branches, providing subtle ornamental quality.

Yellow-green to grayish-green scale-like leaves with pustular glands and bronze winter hue on arborvitae.

Durable, resilient stems of 0.1-0.2 inches (3-5 mm) in diameter create a bushy appearance.

Prominent trunk with textured, peeling bark in grayish to reddish-brown hues define mature arborvitae.

Scientific Classification of Arborvitae

Phylum

Vascular plants

Class

Conifers

Order

Pines and allies

Family

Cypress

Genus

Arborvitaes

Species

Arborvitae

Planting and Growing of Arborvitae

Care Difficulty

Easy

Watering Schedule

Every 3 days

Sunlight Requirements

Full sun

Sunshine Duration

4-6 hours

Ideal Temperature

65-75℉

Soil Type

Potting Mix, Peat Mix

Soil pH

6.5-7.5

Fertilizer Type

Balanced

Pruning Season

Spring, Summer

Pruning Area

Branches, Leaves

Pruning Frequency

2 times a year

Repotting Season

Spring

Pot Type

Plastic, Ceramic

How to Water Arborvitae?

The watering amount for Thuja occidentalis should ensure that the soil is moist but not waterlogged. Typically, 500 ml of water is sufficient per watering session. It is essential to water until the top few inches of soil are evenly moist, taking care not to create any standing water, which can lead to root rot.

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What Are the Sunlight Requirements for Arborvitae?

Sunlight Requirements: Full sun, Partial sun

Duration of light: 4-6 hours daily

Thuja occidentalis thrives in conditions offering full sun to partial sun, ensuring it enjoys four to six hours of optimal light. Proper lighting enhances foliage density, strengthens plant health, and supports a well-rounded structural form, maximizing decorative and functional potential.

What is the best lighting condition for Thuja occidentalis? ›

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What Is the Ideal Temperature Range for Arborvitae?

Ideal Temperature: 65 ~ 75℉

The ideal temperature range for Thuja occidentalis, commonly known as the Northern White Cedar, is between 65°F and 75°F. This range ensures optimal growth and physiological development. In this temperature spectrum, the plant efficiently photosynthesizes, maintains moisture, and facilitates nutrient uptake, leading to healthy foliage and robust growth. It is important to keep the temperature stable within this range to avoid stress that could weaken the plant.

What Soil is Best for Arborvitae?

Soil type: Loam, Sandy loam

Soil PH: 6.5 ~ 7.5

Thuja occidentalis thrives in well-drained soil, which helps prevent root rot and other moisture-related issues. A balance between retaining moisture and allowing excess water to escape is essential for healthy growth and vibrant foliage. This plant prefers soil with moderate fertility. It benefits from the availability of essential nutrients without the risk of burning from excessive fertilization. A fertile soil base supports strong root development and luxuriant foliage. While Thuja occidentalis does not favor waterlogged conditions, it requires consistent moisture. Regular watering ensures the plant remains hydrated, particularly during dry spells, supporting its growth and overall vitality. More About Soil→

How to Fertilize Arborvitae?

Fertilizer type: Balanced

For Thuja occidentalis, it is crucial to apply fertilizers with care to prevent nutrient burn. When applying liquid fertilizers, use approximately 100 ml per plant diluted in a gallon of water for a gentle boost. For slow-release fertilizers, a small handful, roughly equivalent to 50 grams per plant, is sufficient to provide a steady stream of nutrients over time.

How to Prune Arborvitae?

Pruning Time: Spring, Summer

Start by identifying dead or damaged branches. Use clean, sharp pruning shears to cut these branches at the base to ensure a healthy structure is maintained. Shape the plant according to your preference, but keep in mind that Thuja occidentalis naturally grows in a conical form. Focus on gentle shaping to encourage fuller growth. For denser growth, trim the tips of the outer branches lightly. This encourages the plant to produce multiple new shoots, resulting in a bushier appearance. Aim to cut no more than one-third of the total foliage to prevent over-pruning, which can stress the plant and reduce its vitality. More About Pruning Techniques→

How to Propagate Arborvitae plant?

Propagate Time: Spring, Early spring

Choose healthy semi-hardwood cuttings from a mature Thuja occidentalis. The cuttings should be around 6-10 inches long and free from disease or pests. Make sure to cut just below a leaf node for optimal rooting.

Prepare a well-draining medium such as a mixture of peat and perlite. This provides aeration and moisture retention needed for root development. Avoid using garden soil as it can compact and hinder root growth.

Dip the cut end of each cutting in rooting hormone to stimulate root growth and plant it in the prepared medium. Keep the cuttings upright and gently firm the soil around them to eliminate air pockets.

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How to Repot Arborvitae plant?

Repotting frequency: Every 2-3 years

Repotting Thuja occidentalis is necessary when you see roots emerging from drainage holes or the plant's growth appears stunted. Ideally, plan to repot in early spring or autumn when the plant is not actively growing, ensuring minimal stress. It's essential to observe the plant's overall health and look for signs of overcrowding in its current container.

Select a pot that is one size larger than the current one, offering ample space for root expansion. Ensure the pot has sufficient drainage holes to prevent waterlogging, which can lead to root rot. Opting for a pot made of materials like ceramic or terracotta can help with breathability and temperature regulation, crucial for the plant's well-being.

Use a well-draining soil mix combining loam and peat. This mix provides the perfect balance of nutrients and aeration for Thuja occidentalis. The soil's acidity and permeability offer the right environment for the plant to flourish, supporting root health and growth.

Toxicity of Arborvitae

Is Arborvitae toxic to cat?

Arborvitae presents a moderate toxicity risk to cats, creating potential health issues if any portion of the plant is ingested. Consumption may result in observable signs of physical discomfort or distress in felines. It is crucial to observe for any unusual behaviors and symptoms that may indicate pain or illness following exposure. Prompt veterinary intervention is essential for the animal's welfare after ingestion. While the specific toxic compounds in arborvitae are not identified, the whole plant is toxic and poses threats to cats.

Is Arborvitae toxic to dog?

Arborvitae presents a moderate toxicity threat to dogs. Consuming any portion of this plant can result in poisoning. Dogs are at risk of toxicity from eating any plant part, as all sections are deemed harmful. Symptoms of poisoning in dogs may manifest as vomiting, diarrhea, abdominal discomfort, and excessive salivation. In severe instances, ingestion could lead to more critical health issues such as muscle weakness or seizures. It is essential for dog owners to keep their pets away from arborvitae and to diligently observe them if they are in close proximity to the plant. If there's a suspicion of arborvitae poisoning in a dog, it is vital to seek immediate veterinary attention to secure the best possible prognosis for the animal.

WARNING

The judgment on toxicity and danger is for reference only. We DO NOT GUARANTEE any accuracy of such judgment. Therefore, you SHALL NOT rely on such judgment. It is IMPORTANT TO SEEK PROFESSIONAL ADVICE in advance when necessary.

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