Why Is My Arborvitae Turning Yellow?



Arborvitae, also known as Thuja, is a popular evergreen tree or shrub that is commonly found in gardens and landscapes. Its vibrant green foliage and dense growth make it a favorite choice for privacy screens, hedges, and ornamental plantings. However, gardeners often become concerned when they notice their arborvitae turning yellow. This article aims to explore the reasons behind this phenomenon and provide helpful information on how to address the issue.

Understanding Arborvitae

Arborvitae, belonging to the genus Thuja, is a group of evergreen trees and shrubs that are native to North America and parts of Asia. They are known for their tall, columnar shape and dense foliage, which provides excellent privacy and windbreak. Common varieties of arborvitae include Thuja occidentalis (American arborvitae), Thuja plicata (Western red cedar), and Thuja orientalis (Oriental arborvitae).

Arborvitae is highly valued in garden landscapes for its aesthetic appeal and functional benefits. Its vibrant green foliage adds year-round color and texture to the garden, creating a lush and inviting atmosphere. Additionally, arborvitae’s dense growth pattern makes it an ideal choice for creating privacy screens and hedges.

Causes of Yellowing Arborvitae

Lack of Water

Proper watering is essential for maintaining the health and vitality of arborvitae. When arborvitae does not receive an adequate amount of water, it can lead to yellowing leaves. This is because water is crucial for the transport of nutrients within the plant. Without sufficient water, the plant cannot absorb and distribute nutrients properly, resulting in yellowing foliage.

To ensure proper watering for arborvitae, it is important to follow a few guidelines. Water deeply and thoroughly, allowing the water to penetrate the root zone. Avoid shallow watering, as it promotes shallow root growth and increases the risk of drought stress. Monitor the moisture levels in the soil and adjust watering frequency based on the plant’s needs and environmental conditions.

Nutrient Deficiencies

Arborvitae requires a balanced supply of nutrients to thrive. When essential nutrients are lacking in the soil, it can lead to nutrient deficiencies and subsequent yellowing of the foliage. Common nutrient deficiencies in arborvitae include nitrogen, iron, and magnesium.

To address nutrient deficiencies, it is important to conduct a soil test to determine the specific nutrient requirements of the plant. Based on the test results, appropriate fertilizers can be applied to replenish the deficient nutrients. Organic fertilizers, such as compost or well-rotted manure, can also be beneficial in improving soil fertility and nutrient availability.

Pests and Diseases

Arborvitae is susceptible to various pests and diseases that can cause yellowing of the foliage. Common pests that affect arborvitae include spider mites, bagworms, and aphids. These pests feed on the plant’s foliage, causing damage and discoloration.

In addition to pests, arborvitae can also be affected by diseases such as root rot, canker, and needle blight. These diseases can weaken the plant’s immune system and lead to yellowing and browning of the foliage.

To control pests and diseases, it is important to regularly inspect the arborvitae for signs of infestation or infection. Promptly remove any affected branches or foliage and consider using appropriate insecticides or fungicides as recommended by a professional.

Environmental Stress

Arborvitae can experience yellowing foliage due to environmental stress factors. Extreme temperatures, both hot and cold, can cause stress to the plant and result in yellowing leaves. Excessive sunlight, especially in combination with high temperatures, can lead to sunburn and leaf scorch.

Poor soil conditions, such as compacted soil or improper drainage, can also contribute to environmental stress and yellowing of the foliage. Inadequate soil aeration and nutrient availability can hinder the plant’s ability to absorb essential elements, leading to yellowing leaves.

To mitigate environmental stress, it is important to provide appropriate care and maintenance for arborvitae. This includes providing shade during hot summer months, improving soil quality through proper amendment and drainage, and ensuring adequate air circulation around the plant.

Diagnosing Yellowing Arborvitae

When faced with yellowing arborvitae, it is crucial to diagnose the specific cause in order to implement the appropriate treatment. Here are some steps to help diagnose the issue:

  1. Visual Inspection: Carefully examine the arborvitae, paying close attention to the affected foliage. Look for any signs of pests, diseases, or physical damage. Note the pattern of yellowing, whether it starts from the tips, edges, or throughout the entire plant.
  2. Soil Analysis: Conduct a soil test to assess the nutrient levels and pH of the soil. Nutrient deficiencies or imbalances can contribute to yellowing foliage. The soil test will provide valuable information to determine if the issue is related to nutrient deficiencies.
  3. Environmental Assessment: Evaluate the environmental conditions surrounding the arborvitae. Consider factors such as sunlight exposure, temperature extremes, and soil moisture levels. Determine if any environmental stressors could be causing the yellowing.
  4. Pest and Disease Identification: If pests or diseases are suspected, identify the specific pest or disease affecting the arborvitae. Look for signs such as webbing, holes in the foliage, or discoloration patterns. Consult with a local extension office or arborist for accurate identification and treatment recommendations.
  5. History and Care Analysis: Review the history of care and maintenance for the arborvitae. Consider factors such as watering practices, fertilization, pruning, and any recent changes in the garden. Assess if any improper care practices could be contributing to the yellowing.

By carefully analyzing these factors, gardeners can narrow down the potential causes of yellowing arborvitae and make an informed diagnosis. This will guide them in implementing the appropriate treatment and care strategies to restore the health of the plant.

Treating Yellowing Arborvitae

Watering and Fertilization

Once the cause of yellowing arborvitae has been identified, appropriate treatment can be implemented. In the case of water deficiency, it is important to adjust the watering practices to ensure the plant receives adequate moisture. Deep watering is recommended, allowing the water to penetrate the root zone. Mulching around the base of the arborvitae can help retain moisture and regulate soil temperature.

If nutrient deficiencies are the cause of yellowing, fertilization can help replenish the lacking nutrients. Use a balanced fertilizer specifically formulated for arborvitae or evergreen trees. Follow the instructions on the fertilizer package for proper application rates and timing. It is important not to over-fertilize, as this can lead to nutrient imbalances and further stress the plant.

Pest and Disease Control

When pests or diseases are identified as the cause of yellowing arborvitae, appropriate control measures should be taken. For pest infestations, consider using insecticidal soaps, horticultural oils, or insecticides labeled for arborvitae. Follow the instructions carefully and apply the treatments as recommended. Regular monitoring and early intervention are key to preventing further damage.

For diseases, pruning affected branches and disposing of them properly can help prevent the spread of infection. Fungicides may be necessary for certain diseases, but it is important to consult with a professional or local extension office for accurate diagnosis and treatment recommendations.

Environmental Management

To address environmental stressors, take steps to create optimal growing conditions for arborvitae. Provide shade during hot summer months by using shade cloth or planting companion plants that offer protection. Improve soil quality by adding organic matter, such as compost or well-rotted manure, to enhance drainage and nutrient availability. Consider using mulch to regulate soil temperature and conserve moisture.

Proper pruning can also help alleviate stress and promote healthy growth. Remove any dead, damaged, or overcrowded branches to improve air circulation and reduce the risk of disease. Avoid excessive pruning, as this can weaken the plant and make it more susceptible to stress.

By implementing these treatment strategies, gardeners can effectively address the underlying causes of yellowing arborvitae and promote the plant’s recovery and overall health.

Preventing Yellowing Arborvitae

Prevention is key to maintaining the health and vitality of arborvitae and preventing yellowing foliage. Here are some proactive measures that gardeners can take:

Regular Maintenance

Regular maintenance is essential for keeping arborvitae healthy and vibrant. This includes proper pruning to remove dead or diseased branches, promote air circulation, and maintain the desired shape. Pruning should be done during the dormant season to minimize stress on the plant.

Mulching around the base of the arborvitae helps conserve moisture, regulate soil temperature, and suppress weed growth. Apply a layer of organic mulch, such as wood chips or bark, while keeping it away from the trunk to prevent rot.

Proper Watering

Establish a regular watering schedule for arborvitae, especially during dry periods. Deep watering is recommended to encourage deep root growth. Water the plant thoroughly, allowing the water to penetrate the root zone. Avoid shallow watering, as it promotes shallow root development and increases the risk of drought stress.

Monitoring for Pests and Diseases

Regularly inspect arborvitae for signs of pests and diseases. Early detection is crucial for effective control. Monitor the foliage for any discoloration, spots, or abnormal growth. Check the undersides of leaves for signs of pests, such as webbing or tiny insects. Promptly address any pest or disease issues to prevent further damage.

Soil Improvement

Maintaining healthy soil is essential for the overall health of arborvitae. Conduct regular soil tests to assess nutrient levels and pH. Based on the test results, amend the soil with organic matter or appropriate fertilizers to ensure optimal nutrient availability. Improving soil drainage is also important to prevent waterlogged conditions that can lead to root rot.

Proper Planting and Spacing

When planting arborvitae, ensure proper spacing between individual plants to allow for adequate air circulation and prevent overcrowding. This helps reduce the risk of disease and promotes healthy growth. Follow the recommended spacing guidelines for the specific variety of arborvitae being planted.

Regular Monitoring and Care

Regularly monitor the health of arborvitae and address any issues promptly. Keep an eye out for any changes in foliage color, growth patterns, or signs of stress. Provide appropriate care, such as fertilization, pruning, and pest control, as needed.

By implementing these preventive measures, gardeners can minimize the risk of yellowing arborvitae and maintain healthy, vibrant plants in their garden landscapes.

What Are the Common Reasons for Plants to Turn Yellow?

The yellowing of fern leaves may occur due to various reasons. Insufficient sunlight, inadequate watering, nutrient deficiencies, or diseases are common culprits. Lack of chlorophyll production can lead to a pale green or yellow appearance. Identifying the precise cause is crucial in addressing the issue and reviving the plant’s health.


In conclusion, yellowing arborvitae can be a cause for concern among gardeners. However, by understanding the potential causes and implementing the appropriate treatments and preventive measures, it is possible to restore the health and vibrancy of these beautiful evergreen trees.

Proper watering and fertilization are crucial for maintaining the overall health of arborvitae. Adequate moisture and nutrient supply help prevent yellowing foliage caused by water deficiency or nutrient deficiencies. Regular monitoring and control of pests and diseases are also important to prevent damage and yellowing.

Environmental factors, such as extreme temperatures and poor soil conditions, can contribute to yellowing arborvitae. By providing optimal growing conditions, such as shade during hot summer months and improving soil quality, gardeners can mitigate environmental stress and promote healthy growth.

Diagnosing the specific cause of yellowing arborvitae is essential for effective treatment. Through visual inspection, soil analysis, and assessment of environmental factors, gardeners can identify the underlying issue and implement the appropriate measures.

Frequently Asked Questions (FAQs)

Q: Why are the tips of my arborvitae turning yellow?

A: Yellowing tips on arborvitae can be a sign of various issues, including nutrient deficiencies, overwatering, or environmental stress. It is important to assess the specific conditions and care practices to determine the underlying cause and take appropriate action.

Q: Can arborvitae recover from yellowing foliage?

A: In many cases, arborvitae can recover from yellowing foliage with proper care and treatment. Identifying the cause of yellowing and implementing the necessary measures, such as adjusting watering practices, addressing nutrient deficiencies, or controlling pests and diseases, can help the plant regain its health and vitality.

Q: How often should I water my arborvitae?

A: The frequency of watering arborvitae depends on various factors, including the climate, soil type, and plant size. As a general guideline, arborvitae should be watered deeply and thoroughly, allowing the water to penetrate the root zone. It is important to monitor the moisture levels in the soil and adjust watering frequency accordingly.

Q: Can arborvitae tolerate full sun?

A: Arborvitae generally prefers partial shade to full sun exposure. While some varieties can tolerate full sun, prolonged exposure to intense sunlight can lead to sunburn and leaf scorch, resulting in yellowing foliage. Providing some shade during hot summer months can help protect arborvitae from excessive sun exposure.

Q: How can I prevent pests from infesting my arborvitae?

A: To prevent pests from infesting arborvitae, it is important to maintain good garden hygiene and regularly inspect the plants for signs of pests. Avoid over-fertilizing, as excessive nitrogen can attract pests. Consider using organic pest control methods, such as insecticidal soaps or horticultural oils, and encourage beneficial insects that prey on pests.

Q: Can I prune my arborvitae to reduce yellowing foliage?

A: Pruning can help improve the overall health and appearance of arborvitae, but it may not directly address yellowing foliage caused by specific issues. Pruning can remove dead or diseased branches and promote better air circulation, which can indirectly contribute to the plant’s overall health. However, it is important to identify and address the underlying cause of yellowing for effective treatment.

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