Arborvitae are among the most popular evergreen privacy trees in North America. They grow quickly, stay green year-round, and create excellent screens and windbreaks.
So when an arborvitae starts turning brown, it’s understandable to feel concerned.
The good news is that not all browning means your tree is dying. In many cases, arborvitae can recover once the underlying problem is identified and corrected. However, certain types of browning may signal serious stress, disease, root damage, or even tree death.
This guide explains why arborvitae turn brown, how to diagnose the cause, and what you can do to save your tree.
Quick Answer: Why Is My Arborvitae Turning Brown?
Arborvitae commonly turn brown because of:
- Winter burn
- Drought stress
- Overwatering
- Root damage
- Transplant shock
- Natural seasonal needle drop
- Insect infestations
- Fungal diseases
- Salt damage
- Poor planting practices
The location and pattern of the browning often provide clues about the underlying cause.
Is It Normal for Arborvitae to Turn Brown?
Sometimes, yes.
Arborvitae naturally shed older interior foliage every year.
Normal Browning
Characteristics include:
- Brown needles inside the plant
- Green outer growth remains healthy
- Occurs mostly in fall
- Limited to older foliage
This process is called seasonal needle drop.
Concerning Browning
You should investigate if:
- Entire branches turn brown
- Outer foliage browns
- Browning spreads rapidly
- Large sections die back
These symptoms usually indicate stress or damage.
How to Tell If an Arborvitae Is Dying
Signs of serious decline include:
- Entire branches turning brown
- Browning from the top downward
- Sparse foliage
- Cracked bark
- Dead branch tips
- Lack of new growth
- Significant root problems
The sooner you identify the cause, the better the chance of recovery.
General Arborvitae trees (Thuja species) Diseases
Arborvitae trees (Thuja species) are popular evergreens for hedges and landscaping, but they can suffer from several diseases and stress conditions. Here’s a detailed explanation of the main ones:
Phomopsis Twig Blight
This fungal disease primarily affects young shoots in spring. The tips of branches turn brown or ash gray and remain attached for months, giving the tree a scorched look. Tiny black fruiting bodies of the fungus may be visible on the dead tissue. It spreads quickly in wet, humid conditions. Management involves pruning out infected twigs, sterilizing tools, and applying fungicides such as copper or mancozeb during the growing season.
Kabatina Twig Blight
Kabatina blight usually appears on one‑year‑old branch tips, often in late winter or early spring. The affected tips turn brown or gray, and black fruiting structures form at the infection site. Unlike Phomopsis, Kabatina often strikes stressed trees, especially those weakened by drought or poor soil. Sanitary pruning and reducing stress are key, along with fungicide sprays if needed.
Pestalotiopsis Tip Blight
This blight causes tan or brown discoloration at the ends of twigs, often with black fungal dots. It can resemble other blights but tends to affect scattered tips rather than whole sections. Good airflow, pruning diseased tissue, and fungicide applications help control it.
Cercospora Blight
Cercospora blight begins with browning of inner foliage, while the outer tips remain green for a time. This gives the tree a hollowed‑out look. It thrives in dense plantings with poor airflow. Improving spacing, pruning to open the canopy, and fungicide protection are effective measures.
Root Rot (Phytophthora)
Root rot is one of the most serious problems. It occurs in poorly drained soils where water stagnates around the roots. Symptoms include browning from the base upward, poor vigor, and eventual death. Once advanced, arborvitae rarely recover. Prevention is critical: plant in well‑drained soil, avoid overwatering, and amend clay soils with organic matter.
Winter Burn
Although not a disease, winter burn is a common stress condition. Foliage exposed to cold winds dries out and turns brown, especially on the windward side. Deep watering before the ground freezes and using windbreaks or anti‑desiccant sprays can reduce damage.
Bagworms
Bagworms are insect pests that create silk bags hanging from branches. They feed on foliage, causing localized defoliation. Hand‑removing the bags in winter or applying insecticides in summer can control them.
Spider Mites
Spider mites cause stippling and bronzing of foliage, often leaving fine webbing. They thrive in hot, dry weather. Washing foliage with water, applying horticultural oils, or using miticides helps manage infestations.
10 Common Causes of Arborvitae Turning Brown
1. Winter Burn
Winter burn is one of the most common causes of arborvitae browning.
What Happens?
During winter:
- Wind removes moisture from foliage.
- Frozen soil prevents roots from replacing lost water.
The result is dehydration.
Symptoms
- Brown outer foliage
- Browning on exposed sides
- Damage appears in late winter or spring
How to Fix It
- Water thoroughly before winter.
- Apply mulch around the root zone.
- Use burlap wind protection in exposed locations.
2. Drought Stress
Arborvitae require regular moisture, especially during establishment.
Symptoms
- Browning branch tips
- Entire sections turning brown
- Dry soil
Young trees are particularly vulnerable.
How to Fix It
Water deeply:
- Once or twice per week during dry periods
Avoid shallow daily watering.
3. Overwatering and Poor Drainage
Too much water can be just as harmful as too little.
Symptoms
- Yellowing foliage
- Browning branches
- Soft or mushy roots
Why It Happens
Saturated soil reduces oxygen availability.
Roots begin to decline.
How to Fix It
- Improve drainage
- Reduce irrigation
- Avoid planting in waterlogged areas
4. Transplant Shock
Newly planted arborvitae often struggle while establishing roots.
Symptoms
- Browning after planting
- Slowed growth
- Stress during hot weather
How Long Does It Last?
Typically:
- Several weeks to one year
depending on planting conditions.
Recovery Tips
- Water consistently
- Mulch properly
- Avoid excessive fertilization
5. Root Damage
Damaged roots often lead to canopy browning.
Common Causes
- Construction activity
- Digging
- Soil compaction
- Trenching
Symptoms
- Sudden browning
- One-sided decline
- Reduced growth
6. Natural Seasonal Needle Drop
Many homeowners mistake this for disease.
Symptoms
- Browning deep inside the tree
- Healthy green outer foliage
- Occurs annually
This is normal and usually requires no treatment.
7. Bagworms
Bagworms frequently attack arborvitae.
Signs
- Small hanging bags
- Browning branches
- Thinning foliage
Severe infestations can kill trees.
Treatment
- Hand-remove bags
- Use appropriate insecticides when necessary
8. Spider Mites
Spider mites often cause browning during hot, dry weather.
Symptoms
- Speckled foliage
- Bronzing needles
- Fine webbing
Treatment
- Increase moisture
- Spray with water
- Use horticultural oils if needed
9. Fungal Diseases
Several fungal pathogens affect arborvitae.
Common Diseases
- Needle blight
- Branch blight
- Root rot
Symptoms
- Browning branch tips
- Dead patches
- Progressive dieback
Treatment
- Improve airflow
- Avoid overhead watering
- Remove infected branches
10. Salt Damage
Road salt can injure arborvitae.
Symptoms
- Browning on road-facing sides
- Tip burn
- Winter discoloration
Prevention
- Use barriers
- Flush soil in spring
- Limit salt exposure
Arborvitae Turning Brown After Planting
New arborvitae often experience stress after planting.
Common causes include:
- Root disturbance
- Inconsistent watering
- Heat stress
- Planting too deeply
Most recover with proper care.
Arborvitae Turning Brown From the Inside
This is often the least serious form of browning.
Possible causes:
- Seasonal needle drop
- Lack of sunlight inside the canopy
- Aging foliage
If the outer foliage remains green, concern is usually minimal.
Arborvitae Turning Brown From the Top
Top-down browning can indicate:
- Severe drought
- Root problems
- Winter injury
- Disease
This pattern deserves closer inspection.
Arborvitae Turning Brown After Winter
Winter damage commonly appears in spring.
Look for:
- Brown tips
- Brown outer foliage
- Damage on windy sides
Trees often produce new growth later in the season.
Arborvitae Turning Brown in Summer
Summer browning frequently results from:
- Drought stress
- Spider mites
- Root problems
- Heat stress
Check soil moisture first.
Can a Brown Arborvitae Turn Green Again?
It depends.
Foliage That May Recover
- Lightly bronzed foliage
- Winter-burned foliage
- Mild drought stress
Foliage That Will Not Recover
- Completely dead brown branches
- Severely damaged tissue
Dead foliage generally stays brown and must be pruned.
How to Save a Browning Arborvitae
Step 1: Identify the Cause
Look at:
- Browning pattern
- Soil conditions
- Pest activity
- Recent weather
Step 2: Correct Watering Issues
Avoid both:
- Drought
- Saturated soil
Step 3: Mulch Properly
Apply:
- 2–4 inches of mulch
Keep mulch away from the trunk.
Step 4: Inspect for Pests
Check for:
- Bagworms
- Spider mites
Step 5: Prune Dead Branches
Remove:
- Dead
- Broken
- Diseased branches
Do not prune heavily during stress periods.
Arborvitae Care Tips to Prevent Browning
Water Deeply
Especially during drought.
Mulch the Root Zone
Helps regulate moisture and temperature.
Avoid Trunk Damage
Protect from mowers and string trimmers.
Plant in Well-Drained Soil
Poor drainage often causes root problems.
Monitor for Pests
Early detection prevents severe damage.
Arborvitae Browning Troubleshooting Chart
| Symptom | Likely Cause |
|---|---|
| Brown interior needles | Seasonal needle drop |
| Brown tips after winter | Winter burn |
| Browning after planting | Transplant shock |
| Entire branches brown | Root stress or disease |
| Browning on road side | Salt damage |
| Browning with bags attached | Bagworms |
| Bronzed foliage with webbing | Spider mites |
| Top turning brown | Drought or root issues |
When to Call an Arborist
Seek professional help if:
- More than 50% of the tree is brown
- Root damage is suspected
- Disease is spreading rapidly
- Multiple arborvitae are declining
Early diagnosis often saves valuable trees.
Final Thoughts
Seeing an arborvitae turn brown can be alarming, but many cases are caused by temporary stress rather than permanent decline. Seasonal needle drop, winter burn, transplant shock, and drought stress are among the most common reasons arborvitae develop brown foliage.
The key is to identify the pattern of browning and address the underlying cause quickly. With proper watering, mulching, pest management, and care, many arborvitae can recover and continue serving as beautiful privacy screens for years to come.
Frequently Asked Questions
Why is my arborvitae turning brown?
Common causes include drought, winter burn, pests, diseases, and natural needle drop.
Can a brown arborvitae recover?
Yes, if the underlying cause is corrected before severe damage occurs.
Is it normal for arborvitae to turn brown inside?
Yes. Seasonal needle drop often causes interior browning.
How often should I water arborvitae?
Generally once or twice weekly during dry periods, depending on weather and soil.
Will dead brown branches turn green again?
No. Dead branches typically remain brown and should be pruned.
Can overwatering cause arborvitae browning?
Yes. Poor drainage and excessive watering can damage roots.
What do bagworms look like on arborvitae?
They appear as small hanging bags made from needles and plant material.
How do I prevent winter burn?
Water before winter, mulch roots, and use wind protection when needed.
Why is only one side of my arborvitae brown?
This may indicate salt damage, wind exposure, root injury, or localized stress.
Should I cut off brown arborvitae branches?
Yes, if they are dead. Prune back to healthy green growth.