Arborvitae turning brown is one of the most common — and most alarming — things that happens to homeowners after planting a privacy hedge. The good news: in most cases, browning arborvitae is fixable, and understanding the cause is the key to the solution. This guide walks through every common cause of arborvitae browning, how to identify which one you’re dealing with, and exactly what to do about it.
Quick Diagnosis: What Does the Browning Look Like?
| Pattern of Browning | Most Likely Cause |
|---|---|
| South or west side only, late winter/early spring | Winter burn (sun scald) |
| Tips browning, spreading inward, hot dry summer | Drought stress |
| Bag-shaped pouches hanging from branches | Bagworms |
| Stippled, dull foliage; fine webbing; hot weather | Spider mites |
| Bottom of plant browning, spreading upward | Root rot or poor drainage |
| Interior browning only, outer foliage green | Normal seasonal needle drop |
| Browning from bottom up, stripped foliage | Deer browse |
| Entire plant browning rapidly after planting | Transplant shock or planting too deep |
Cause #1: Winter Burn (The Most Common Cause)
Winter burn is by far the most common cause of arborvitae browning — and the one that causes the most unnecessary panic. It looks alarming but is rarely fatal.
What it looks like
Browning appears on the south and/or west-facing sides of the plant in late winter or early spring (February through April). The north and east sides remain green. The browning is most severe on the most exposed foliage and fades toward the interior.
What causes it
Winter burn is desiccation — the foliage loses moisture on sunny, windy winter days while the ground is frozen and the roots can’t replace that moisture. The sun and wind on the south and west sides drive the most moisture loss, which is why those sides brown first. It’s most severe in the first 1–2 winters before the root system is fully established.
Which varieties are most affected
Emerald Green Arborvitae is the most susceptible to winter burn. Green Giant is more resistant. Elegantissima is less prone due to its vertical frond orientation.
What to do
- Wait: In most cases, winter-burned arborvitae recover on their own as temperatures warm and the ground thaws. New growth in spring will cover the browned foliage. Do not prune brown foliage until late spring — wait to see what recovers.
- Water in fall: Water deeply in October and November before the ground freezes. Well-hydrated plants suffer far less winter burn than dry ones.
- Burlap wrap: Wrap with burlap (not plastic) in late fall for the first 1–2 winters on exposed sites. Burlap blocks wind and sun without trapping heat.
- Anti-desiccant spray: Apply an anti-desiccant (like Wilt-Pruf) to the foliage in late fall. This coats the needles and reduces moisture loss through winter.
- Mulch: A 3–4 inch layer of mulch over the root zone insulates the soil, keeping it from freezing as deeply and allowing roots to absorb moisture longer into fall and earlier in spring.
Will it recover? Yes, in most cases. If the buds are still green and flexible (scratch the stem — green underneath means alive), the plant will push new growth in spring that covers the brown. If the stems are brittle and brown all the way through, that section is dead and can be pruned out.
Cause #2: Drought Stress
What it looks like
Browning starts at the tips of branches and spreads inward. It typically appears during or after a hot, dry period in summer. The browning is more uniform across the plant (not just one side) and progresses from the outside in.
What causes it
Arborvitae — especially newly planted ones in their first 1–2 years — have shallow root systems that dry out quickly. Extended dry periods without supplemental watering cause the foliage to desiccate from the tips inward. Established plants (3+ years) are much more drought-tolerant but can still show stress in severe droughts.
Which varieties are most affected
All varieties can suffer drought stress, but newly planted trees of any variety are most vulnerable. Among established plants, Emerald Green is the least drought-tolerant. Elegantissima is the most drought-tolerant once established.
What to do
- Water immediately and deeply: Soak the root zone thoroughly — a slow trickle for 30–45 minutes is better than a quick spray. The goal is to wet the soil 12–18 inches deep.
- Establish a watering schedule: In the first year, water 2–3 times per week during dry periods. In year 2, once or twice per week. Established plants need water during any 2+ week dry spell.
- Mulch: A 3–4 inch layer of wood chip mulch over the root zone dramatically reduces moisture loss and is the single best thing you can do to prevent drought stress.
- Drip irrigation: For a long hedge row, drip irrigation is the most efficient way to deliver consistent moisture directly to the root zone.
Will it recover? Mild drought stress (tip browning only) usually recovers with consistent watering — the brown tips won’t green back up, but new growth will cover them. Severe drought stress that browns large sections may be permanent in those areas, though the plant often survives and regrows from the interior.
Cause #3: Bagworms
What it looks like
You’ll see small, spindle-shaped bags (1–2 inches long) hanging from the branches, made of silk and bits of foliage. The surrounding foliage browns as the larvae inside feed on it. Bagworms are most active in summer (June–August) and the damage becomes most visible in late summer and fall.
What causes it
Bagworm moths lay eggs inside the bags in fall. The eggs hatch in late spring and the tiny larvae immediately begin feeding on foliage and building their protective bags. Each larva feeds all summer, stripping foliage as it grows. A heavy infestation can defoliate and kill an arborvitae in a single season.
Which varieties are most affected
All arborvitae varieties are susceptible to bagworms. Green Giant has slightly better resistance than Emerald Green but is not immune. Bagworms are most common in the Midwest and Mid-Atlantic states.
What to do
- Hand-pick bags (fall and winter): After the larvae have pupated (late August onward), hand-pick every bag you can reach and destroy them — drop in a bucket of soapy water or bag and trash. Each bag contains hundreds of eggs. This is the most effective control for small infestations.
- Bt spray (late spring): Apply Bacillus thuringiensis (Bt) — an organic biological insecticide — in late May to early June when larvae are newly hatched and small. Bt is highly effective on young larvae and harmless to birds, bees, and other wildlife. Timing is critical — Bt is much less effective on large larvae.
- Spinosad or permethrin (larger infestations): For heavy infestations, apply spinosad or permethrin in late May to early June. Follow label directions carefully.
- Monitor annually: Check your arborvitae for bags every fall and winter. Early detection and hand-picking prevents populations from exploding.
Cause #4: Spider Mites
What it looks like
Foliage looks stippled, dull, and grayish rather than a clean brown. Look closely for fine webbing between branches, especially on the undersides of foliage. Spider mite damage is most common in hot, dry weather (July–August) and on plants that are already stressed.
What causes it
Spider mites are tiny arachnids (not insects) that pierce foliage and suck out plant juices. They reproduce explosively in hot, dry conditions — populations can double in just a few days. They’re most problematic on Emerald Green Arborvitae in hot summers.
What to do
- Confirm with the tap test: Hold a white piece of paper under a branch and tap sharply. If tiny moving specks fall onto the paper, you have spider mites.
- Strong water spray: A strong jet of water from a hose knocks mites off the foliage and disrupts their colonies. Repeat every 3–5 days for 2–3 weeks.
- Insecticidal soap or neem oil: Apply to all foliage surfaces, especially undersides. Repeat every 7–10 days for 3 applications. Most effective in the morning or evening when temperatures are cooler.
- Miticide: For severe infestations, use a miticide labeled for spider mites on arborvitae. Rotate products to prevent resistance.
- Avoid drought stress: Stressed plants are far more susceptible to spider mites. Consistent watering and mulching is the best prevention.
Cause #5: Root Rot (Phytophthora)
What it looks like
Browning starts at the base of the plant and progresses upward. The lower branches brown and die first while the top remains green initially. The plant may look wilted even after watering. Roots, when examined, are dark brown or black and mushy rather than white and firm.
What causes it
Root rot is caused by water mold pathogens (primarily Phytophthora) that thrive in waterlogged, poorly drained soil. Planting in low spots, heavy clay without drainage, or overwatering are the primary causes. Once established, root rot is very difficult to reverse.
What to do
- Improve drainage immediately: If the site stays wet, the plant will not recover without drainage improvement. Install a French drain, raise the planting bed, or transplant to a better-drained location.
- Reduce watering: If overwatering is the cause, reduce frequency immediately. Allow the soil to dry somewhat between waterings.
- Fungicide drench: Apply a phosphonate fungicide (like Agri-Fos) as a soil drench around the root zone. This won’t cure existing root rot but can slow progression and protect healthy roots.
- Prevention is key: Plant arborvitae in well-drained soil, never in low spots. If your soil is heavy clay, plant slightly high (root ball 1–2 inches above grade) to improve drainage around the root zone.
Will it recover? Mild root rot caught early can sometimes be arrested with drainage improvement and fungicide treatment. Severe root rot — where more than half the root system is affected — is usually fatal. Replacement with a better-drained site is often the best solution.
Cause #6: Normal Interior Needle Drop (Not a Problem)
What it looks like
The interior foliage (closest to the trunk, deep inside the canopy) turns yellow-brown and drops in fall. The outer foliage remains green. This is most noticeable in September and October.
This is completely normal — arborvitae shed their oldest interior needles every fall, just like deciduous trees drop leaves. It’s not a disease, not a pest, and not a sign of stress. The outer foliage that’s visible stays green year-round. No action needed.
Cause #7: Deer Browse
What it looks like
Foliage is stripped or ragged from the bottom up, typically from ground level to about 5–6 feet (the reach of a deer). The damage is most severe in winter when other food sources are scarce. You may see hoof prints or deer droppings nearby.
Which varieties are most affected
Emerald Green Arborvitae is heavily browsed by deer — it’s one of their favorite winter foods. Green Giant Arborvitae is rarely browsed and is the best choice in high-deer areas.
What to do
- Deer repellent spray: Apply a repellent (like Bobbex or Deer Off) to the foliage in fall and reapply after rain. Most effective when applied before deer establish a feeding pattern.
- Fencing: The most reliable protection — install wire fencing around individual plants or the entire hedge row. Must be at least 8 feet tall to prevent deer from jumping over.
- Burlap wrap: Wrapping the lower portion of the plant with burlap in winter physically blocks deer access to the foliage.
- Switch varieties: In high-deer areas, replace Emerald Green with Green Giant, which deer rarely touch. This is the most permanent solution.
Cause #8: Transplant Shock or Planted Too Deep
What it looks like
The entire plant browns rapidly — within weeks of planting. All foliage turns brown from the outside in. The plant may look fine for 2–4 weeks after planting, then crash suddenly.
What causes it
Two common planting mistakes cause this: planting too deep (burying the root flare) or severe root disturbance during planting. When the root flare is buried, the trunk begins to rot and the plant can’t move water and nutrients. Severe root disturbance prevents the plant from establishing before summer heat arrives.
What to do
- Check planting depth immediately: The root flare (where the trunk widens at the base) should be at or slightly above soil level. If it’s buried, carefully remove soil from around the base to expose it.
- Water consistently: Newly planted arborvitae need deep, consistent watering — 2–3 times per week during dry periods in the first year.
- Reduce stress: Mulch heavily, avoid fertilizing in the first year, and protect from wind and extreme sun if possible.
When to Replace vs. When to Wait
| Situation | Recommendation |
|---|---|
| Winter burn, buds still green | Wait — will likely recover in spring |
| Drought stress, tips only | Water consistently — new growth will cover brown tips |
| Bagworms, caught early | Treat immediately — plant can recover |
| Bagworms, severe defoliation | Replace — arborvitae rarely recover from complete defoliation |
| Spider mites, mild | Treat — plant will recover with new growth |
| Root rot, early stage | Improve drainage + fungicide — may recover |
| Root rot, severe | Replace in a better-drained location |
| Interior needle drop only | Normal — no action needed |
| Deer browse, lower half stripped | Protect remaining plant; consider replacing with Green Giant |
Preventing Arborvitae Browning: The Essentials
Most arborvitae browning is preventable with good planting and care practices:
- Plant at the right depth: Root flare at or just above soil level. Never bury the trunk.
- Mulch every plant: 3–4 inches of wood chip mulch over the root zone prevents drought stress, moderates soil temperature, and reduces winter burn risk.
- Water consistently in years 1–2: The most critical window. Deep, consistent watering builds a strong root system that handles stress in later years.
- Water deeply in fall: A deep watering in October–November before the ground freezes dramatically reduces winter burn.
- Choose the right variety for your site: In high-deer areas, plant Green Giant. In dry or sandy soil, plant Elegantissima. In Zone 3–4, plant Emerald Green.
- Inspect for bagworms every fall: Hand-pick bags before eggs hatch in spring. Five minutes of inspection in October prevents a summer infestation.
- Avoid planting in wet spots: Root rot is almost always a site problem. Choose well-drained locations or build raised beds.
🌲 Related: Which Arborvitae Should I Plant? Complete Variety Comparison →
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