Why Is My Arborvitae Turning Brown? A Rochester Diagnosis Guide

By Margaret Ellison, Tree & Shrub Health. Last updated: June 25, 2026

Arborvitae are the workhorse privacy screen of Monroe County yards, and they brown for predictable reasons. The single most useful thing you can do before panicking is to note two details: where on the plant the brown shows up, and when it appeared. Those two clues sort most cases in minutes.

Where on the arborvitae is the brown showing up?

Location is your best diagnostic shortcut. Brown on the outer tips facing the road, the prevailing wind, or the winter sun points to environmental burn, not disease. Brown on the side facing your driveway or street in late winter points to road salt. Brown deep inside the plant, near the trunk, with green tips still healthy is usually normal seasonal needle shed. Brown in dense, dead, cone-shaped clumps that turn out to be little bags is bagworm. A sharp browse line at deer height is, of course, deer.

When the browning is uniform across the whole plant and the inner stems snap dry, the problem is more likely at the roots. That is the one pattern worth taking seriously fastest.

Is it winter burn from Rochester's Zone 5b-6a winters?

This is the most common cause we see in spring. Arborvitae are evergreen, so they keep losing moisture through their foliage all winter. When the ground is frozen, the roots cannot replace that water, and lake-effect wind plus bright late-winter sun dries the foliage faster than it can recover. The result is browning on the windward and sunny faces, often appearing suddenly in March and April.

Winter burn looks alarming but is frequently survivable. If the buds and small twigs behind the brown foliage are still flexible and green when you scratch the bark, the plant will usually push new growth. Protecting vulnerable plants ahead of winter, including the use of anti-desiccant sprays for evergreens against winter burn, reduces how badly they brown the following spring. Burlap windbreaks and good fall watering help too.

Could it be road salt damage?

In a Rochester winter, salt spray from plows and runoff from salted driveways collects on the nearest plants. Arborvitae are notably salt-sensitive. The tell is browning concentrated on the side facing the road or pavement, usually worst at the bottom and on the spray-facing side, showing up as the snow melts. Salt in the soil also pulls moisture away from roots, compounding the damage. If your screen lines a salted route, the pattern of road salt damage on trees and shrubs is worth ruling in or out before you assume disease. Flushing the root zone with water in early spring can help dilute accumulated salt.

Is some browning actually normal?

Yes, and this one causes needless worry every autumn. Arborvitae naturally shed their oldest, innermost foliage. In fall you may see interior leaves turn yellow, then bronze, then brown and drop, while the outer canopy stays green. This is seasonal flagging, not death. The rule of thumb: if the brown is inside and the outer tips are green and growing, it is almost certainly normal. If the brown is on the outside and spreading inward, that is a problem to investigate.

Could it be bagworms or another pest?

Bagworms are the pest most likely to brown an arborvitae from the inside out. The larvae build spindle-shaped bags covered in bits of the host foliage, so the bags hide in plain sight and look like small cones. By the time browning is obvious, a heavy population can defoliate sections of a hedge. Arborvitae and spruce do not always recover from severe defoliation the way deciduous plants do, so early detection matters. If you find those bags, our guide to bagworms on arborvitae and spruce in Rochester walks through timing and control. Spider mites can also stipple and bronze foliage in hot, dry stretches.

Could deer be the cause?

Deer browse arborvitae heavily, especially in winter when other food is scarce, and Monroe County's deer pressure is significant in many neighborhoods. The signature is a clean, flat browse line: foliage stripped to a uniform height from the ground up to about where a deer can reach, with bare, ragged stems below and green above. Damage to trees and shrubs from deer and vole browsing is mechanical, not a disease, but the stressed plant can then brown further. Repeated browsing thins a hedge permanently because arborvitae do not readily regrow from old, bare wood.

What if the whole plant is browning at once?

Uniform, whole-plant browning is the pattern that should move fastest, because it often signals trouble at the roots: heavy clay soil that stays waterlogged, root rot, a girdling root, planting too deep, or transplant stress on a recently installed screen. Rochester's dense glacial clay holds water, and arborvitae roots resent sitting wet. This category overlaps with the broader question of evergreen trees turning brown in Rochester, where root and soil problems are common culprits. A soil and root inspection by a certified arborist is the reliable way to separate a salvageable plant from one that is already gone.

FAQ

Will a brown arborvitae turn green again? Sometimes. If the browning is winter burn or salt and the buds behind it are still green and pliable, the plant usually pushes new growth in spring. Foliage killed outright on bare interior wood typically will not refill, because arborvitae do not regrow from old wood.

When should I worry about a browning arborvitae? Worry when the brown is on the outside and spreading inward, when the whole plant browns uniformly, or when stems snap dry instead of bending. Inner browning with green outer tips in fall is usually just normal shedding.

Should I cut off the brown parts? Wait until you can tell whether the wood behind the brown is alive. Scratch a twig: green and moist means wait for new growth, brown and brittle means that section is dead. Prune dead wood after you confirm the cause.

How do I tell winter burn from a disease? Winter burn follows wind and sun exposure (one side or the tops) and appears in late winter and early spring. Diseases and root problems tend to ignore exposure, browning the plant more uniformly or from the base up. An arborvitae that browns evenly all over is more likely a root or soil issue than winter burn.

Sources

• Monster Tree Service of Rochester
• Cornell University: Home Gardening Resources
• NYS Department of Environmental Conservation, trees and forests: https://dec.ny.gov/nature/forests-trees
• USDA Forest Service: Urban and Community Forestry