Browning arborvitae can be a heart-wrenching sight for any homeowner. These evergreen shrubs are known for their vibrant green foliage, making them a popular choice for privacy screens, hedges, and foundation plantings. However, when arborvitae turn brown, it can be a sign of various underlying issues that need to be addressed promptly to prevent further damage or even loss of the plant.

1. Environmental Stressors:

   a) Drought Stress: Arborvitae are relatively drought-tolerant, but prolonged periods without adequate water can cause the foliage to turn brown and crispy. Ensure regular watering, especially during hot and dry spells.

   b) Heat Stress: Excessive heat can also stress arborvitae, leading to browning. Provide shade during the hottest parts of the day, or consider planting heat-tolerant varieties.

   c) Cold Damage: Arborvitae can be susceptible to cold damage, especially in regions with harsh winters. Protect the plants with burlap or frost blankets during extreme cold spells.

2. Pest and Disease Problems:

   a) Bagworms: These pests feed on arborvitae foliage, causing it to turn brown and unsightly. Inspect for bagworms regularly and remove them by hand or apply insecticides if necessary.

   b) Aphids: Aphids are tiny insects that suck the sap from arborvitae leaves, causing them to turn yellow and brown. Use insecticidal soap or neem oil to control aphid infestations.

   c) Fungal Diseases: Fungal diseases, such as needle blight and root rot, can cause arborvitae foliage to turn brown and fall off. Proper watering, good drainage, and fungicides can help manage these diseases.

3. Improper Planting and Care:

   a) Planting Depth: Planting arborvitae too deeply can suffocate the roots, leading to browning foliage. Ensure the root flare is at or slightly above the soil level.

   b) Soil Conditions: Arborvitae prefer well-drained, acidic soil. If the soil is too alkaline or compacted, it can cause the foliage to turn brown. Amend the soil with organic matter and consider a soil test to determine the pH level.

   c) Fertilization: Over-fertilization or using the wrong type of fertilizer can burn the roots and cause browning foliage. Follow the recommended fertilization schedule for arborvitae and avoid fertilizers high in nitrogen.

4. Transplant Shock:

   a) Recent Transplanting: Newly transplanted arborvitae may experience transplant shock, which can manifest as browning foliage. Provide extra care during this period, including regular watering and protection from harsh elements.

   b) Improper Transplanting: Improper transplanting techniques, such as damaging the roots or not backfilling the hole properly, can also cause browning foliage. Handle the plant carefully during transplanting and ensure the root ball is firmly settled in the new location.

5. Natural Browning:

   a) Seasonal Changes: Arborvitae may naturally experience some browning of the inner foliage during the fall and winter months. This is a normal process and the foliage should recover in the spring.

   b) Aging: As arborvitae age, some browning of the lower branches is common. This is a natural part of the aging process and does not necessarily indicate a problem.

Conclusion:

Browning arborvitae can be caused by various factors, ranging from environmental stressors to pest and disease problems. Proper care, including regular watering, appropriate fertilization, and pest and disease management, is essential to maintain healthy, vibrant arborvitae. If you notice browning foliage, promptly identify the cause and take the necessary steps to address the issue before it becomes more severe.

Frequently Asked Questions (FAQs):

1. What are the signs of drought stress in arborvitae?

   • Wilting foliage
   • Brown and crispy leaves
   • Drooping branches

2. Which pests commonly affect arborvitae?

   • Bagworms
   • Aphids
   • Spider mites

3. How can I prevent fungal diseases in arborvitae?

   • Water properly to avoid waterlogged soil
   • Improve drainage if necessary
   • Apply fungicides according to the manufacturer's instructions

4. What is transplant shock, and how can I help my newly transplanted arborvitae?

   • Transplant shock is a temporary condition that occurs when a plant is moved to a new location
   • Provide extra care during this period, including regular watering and protection from harsh elements

5. Is it normal for arborvitae to experience some browning during the fall and winter?

   • Yes, it is a natural process known as seasonal browning and the foliage should recover in the spring