You walk outside one morning and your arborvitae looks like it got hit with a blowtorch. Brown patches everywhere. Maybe the whole thing is turning bronze from the inside out, or maybe just one side looks scorched while the rest stays green.
Take a breath. Browning arborvitae is one of the most common questions we hear at Nature Hills, and the good news is that the cause is almost always identifiable if you know where to look. The bad news? There are at least eight different reasons your arborvitae could be turning brown, and each one calls for a different response.
Let's walk through them one by one so you can figure out exactly what's going on with your trees.
1. Winter Burn
Symptoms: Foliage turns brown or bronze on the windward side of the tree, usually showing up in late winter or early spring. The damage is worst on the side facing prevailing winds. Tips and outer foliage are affected first.
What's happening: Cold, dry winter winds pull moisture out of the foliage faster than the frozen root system can replace it. The needles literally dry out and die. This is called desiccation, and it's the single most common cause of arborvitae browning in zones 3 through 5.
The fix: For established trees, the damaged foliage won't turn green again, but the tree will push new growth in spring to fill in. Be patient. For prevention, wrap exposed trees in burlap before winter (don't let the burlap touch the foliage), or apply an anti-desiccant spray like Wilt-Pruf in late fall. Soak the root zone deeply before the ground freezes so the tree goes into winter fully hydrated.
Best pick for wind-exposed sites: Green Giant Arborvitae (Zones 5-8, 40-60 ft. tall, 12-18 ft. wide) handles wind better than most varieties due to its dense branching and vigorous growth rate of 3-5 feet per year.
2. Drought Stress
Symptoms: Browning starts from the interior of the tree and works outward. Foliage feels dry and crispy. The tree may look thin overall, with the inner canopy turning straw-colored before the outer growth shows stress.
What's happening: Arborvitae are not the drought-tough conifers some people assume. They need consistent moisture, especially during the first two growing seasons after planting. When they don't get enough water, the tree sacrifices its oldest interior foliage first to conserve resources for the branch tips.
The fix: Water deeply and slowly. A soaker hose running for 30-45 minutes twice a week beats a quick spray from a garden hose every day. Mulch the root zone 2-3 inches deep (keep it away from the trunk) to hold moisture and regulate soil temperature. For newly planted trees, don't rely on rainfall alone for the first two full years.
Container-grown arborvitae from Nature Hills establish faster than field-dug stock because the root system arrives intact and ready to grow. That head start matters when drought stress is a concern.
3. Spider Mites
Symptoms: Foliage develops a stippled, bronzed, or yellowish appearance. If you look closely, you may see fine webbing between branches, especially toward the interior. Damage is worst during hot, dry summers.
What's happening: Spider mites are tiny (nearly invisible to the naked eye) and they feed by piercing individual cells on the foliage and sucking out the contents. A heavy infestation can bronze out entire sections of the tree in a matter of weeks.
How to confirm: Hold a white piece of paper under a branch and tap the branch sharply. If you see tiny specks moving on the paper, you've got mites.
The fix: A strong blast of water from the hose knocks mites off and disrupts their lifecycle. Repeat every few days for two weeks. For heavy infestations, use insecticidal soap or horticultural oil, making sure to spray the undersides of foliage where mites hide. Avoid broad-spectrum insecticides. They kill the beneficial predatory insects that keep mite populations in check naturally, which makes the problem worse long term.
4. Bagworms
Symptoms: Small, cone-shaped bags (1-2 inches long) hanging from branches. Each bag is covered in bits of foliage, making it look like a tiny pinecone or a piece of the tree itself. Heavy infestations strip branches bare, leaving brown, defoliated sections.
What's happening: Bagworm caterpillars build portable cases out of silk and plant material. They feed on arborvitae foliage from inside these bags, and a severe infestation can completely defoliate a tree. Unlike some pests, bagworm damage on arborvitae is often permanent because evergreens can't regenerate foliage on bare branches the way deciduous trees can.
The fix: If you catch them early and the infestation is light, hand-pick the bags off the tree and destroy them. Do this in fall or winter before the eggs hatch in spring. For larger infestations, spray with Bt (Bacillus thuringiensis) in late spring when the caterpillars are small and actively feeding. Timing matters with Bt. It works on young larvae but becomes less effective once the caterpillars are larger and sealed inside their bags.
5. Root Rot (Phytophthora)
Symptoms: Browning starts at the bottom of the tree and works upward. Lower branches die first. The trunk base may feel soft or show dark, water-soaked areas. The tree declines over weeks or months, not overnight.
What's happening: Phytophthora is a soil-borne water mold that attacks roots in waterlogged conditions. It thrives in heavy clay soils, low-lying areas, and anywhere drainage is poor. Once the roots are compromised, the tree can't take up water or nutrients, and the foliage dies from the ground up.
The fix: This one is tough. If the tree is already showing significant dieback, it may not recover. Prevention is everything: plant arborvitae in well-drained soil, amend heavy clay with organic matter at planting time, and never let them sit in standing water. If you're replacing a tree that died from root rot, improve the drainage before replanting. Raised beds or berms can help in problem areas.
Choosing naturally vigorous varieties helps too. North Pole Arborvitae (Zones 3-7, 10-15 ft. tall, 3-5 ft. wide) is a tough, cold-hardy columnar variety that handles a range of soil conditions better than many cultivars.
6. Natural Interior Browning (Seasonal Needle Drop)
Symptoms: Interior foliage turns brown and drops in autumn, while the outer canopy stays green. The browning is evenly distributed throughout the tree, not concentrated on one side or in one section.
What's happening: This is completely normal. Arborvitae are evergreen, but "evergreen" doesn't mean "every needle lives forever." The oldest interior foliage is shed every year, usually in fall. The tree replaces it with new growth at the branch tips each spring. Think of it like the tree cleaning house.
The fix: Nothing. Leave it alone. You can shake out the dead needles by hand if they bother you, but the tree is healthy. If you're seeing this for the first time, it can look alarming, but it's one of the most normal things an arborvitae does. Every arborvitae owner goes through this moment of panic at least once.
7. Dog Urine Damage
Symptoms: Yellowing or browning on one side of the tree, concentrated at dog height (roughly the lower 2-3 feet). Usually affects one or two trees in a row, not the entire hedge.
What's happening: Dog urine is high in nitrogen and salts. Repeated exposure burns the foliage on contact and can damage the root zone. If your neighbor's dog has a favorite spot, or your own dog has claimed a particular tree, you'll see localized burn damage that doesn't match any disease or pest pattern.
The fix: Rinse the affected foliage with water immediately when you catch it. For ongoing problems, a small decorative fence or garden border around the base of the trees redirects traffic. Damaged foliage won't recover, but new growth will fill in if you stop the exposure. Training the dog to use a different spot is the real long-term solution.
8. Transplant Shock
Symptoms: General browning, wilting, or lackluster foliage during the first growing season after planting. The tree looks stressed but doesn't show signs of pests, disease, or mechanical damage.
What's happening: The tree is adjusting to its new environment. Even with a healthy root system, the transition from the nursery container to your yard is a big change. Differences in soil type, sun exposure, water availability, and wind can all cause temporary stress while the roots establish.
The fix: Water consistently (deep and slow, not frequent and shallow). Mulch the root zone. Don't fertilize in the first season. Give the tree time. Most container-grown arborvitae recover by the second growing season and take off from there. Avoid the temptation to overwater. More arborvitae are killed by overwatering after transplant than underwatering.
When to Worry vs. When to Wait
Not every brown arborvitae is a dying arborvitae. Here's a quick framework:
Wait and watch:
- Interior browning in autumn (seasonal needle drop, totally normal)
- Browning on one side after a harsh winter (winter burn, new growth will fill in)
- First-season stress after planting (transplant shock, keep watering)
Act now:
- Browning from the base upward (root rot, check drainage immediately)
- Visible bags hanging from branches (bagworms, hand-pick or spray Bt)
- Stippled foliage with webbing in summer (spider mites, start hosing them off)
- Entire tree browning rapidly with no obvious cause (call your local extension office for a diagnosis)
The key question is always: Is this getting worse, or is it stable? Stable browning that matches one of the "wait" categories above is usually fine. Progressive browning that's spreading week over week needs attention.
Best Arborvitae for Problem Resistance
If you're planting new arborvitae or replacing trees that didn't make it, choosing the right variety for your conditions eliminates most of the problems on this list before they start.
Green Giant Arborvitae (Zones 5-8, 40-60 ft. tall, 12-18 ft. wide) is the workhorse. Fast growing at 3-5 feet per year, naturally resistant to bagworms and deer, and tough enough to handle wind exposure. If you have the space and you're in zone 5 or warmer, this is the default choice for privacy screens and hedges.
Emerald Green Arborvitae (Zones 3-7, 12-15 ft. tall, 3-4 ft. wide) is the pick for colder climates and tighter spaces. Its narrow, columnar form fits where Green Giant won't, and it handles zone 3 winters that would damage less hardy varieties. Give it some wind protection in exposed sites and it performs beautifully.
North Pole Arborvitae (Zones 3-7, 10-15 ft. tall, 3-5 ft. wide) is an excellent cold-hardy option with a tight, upright habit. It holds its form well under snow load, making it a strong choice for northern gardeners who want structure without constant maintenance.
Browse the full Arborvitae collection at Nature Hills to find the right fit for your zone and space.
The Bottom Line
Brown arborvitae are fixable more often than not. The trick is identifying the cause correctly before you start throwing solutions at it. Match the browning pattern to the list above, rule out the easy explanations first (seasonal needle drop, winter burn, transplant shock), and then investigate the more serious possibilities if the browning is progressive.
And remember: container-grown arborvitae from a reputable nursery arrive with intact, established root systems that give you a real head start on avoiding transplant stress, drought problems, and root issues. A healthy tree planted in the right spot with proper watering is the best defense against every problem on this list.
