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How to Tell if an Arborvitae Is Dying: The Scratch Test

Brown arborvitae foliage is often seasonal shedding, not death. Scratching the bark and checking where the brown sits separates the two in a minute.

By Zakaria 3 min read Save to Pinterest — opens Pinterest in a new tab
A clipped arborvitae hedge in full green, with shrubs planted along its base and a browning potted conifer nearby
Photo: Famartin, CC BY-SA 4.0, via Wikimedia Commons
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Most brown arborvitae are not dying. Two checks — a thumbnail scratch and where the brown sits — separate a plant that is shedding normally from one that is in real trouble, and they take about a minute.

The scratch test

Take a thumbnail, or the back of a knife, and remove a small patch of the thin outer bark on a branch.

This table answers the question on its own
Where you scratchGreen underneathBrown underneath
Outer twigThat twig is aliveDead twig — test further in
Main branchBranch alive, tips may regrowBranch dead to that point
Trunk, mid-heightPlant aliveTest lower
Trunk, near the basePlant is alive — be patientPlant is dead

Work from the outside in

Start at a twig tip and move toward the trunk until you hit green. The point where brown becomes green is how far back the damage goes — and it is usually less far than the foliage suggests.

Where the brown sits

This is the detail that turns an alarming autumn into a non-event.

Normal shedding: arborvitae drop their oldest foliage, which is the growth nearest the trunk. A band of orange-brown appears inside the plant while the outer surface stays green, and the dead material shakes out. Every healthy specimen does this.

A problem: brown at the tips and outer surfaces, especially on one side, with greener growth deeper in. That is drought, winter burn, or roots that are not working.

The usual causes of real browning

  • Drought, especially in years one and two. The commonest killer of newly planted arborvitae, and the symptoms arrive weeks after the dry spell that caused them. Water deeply and regularly through the first two growing seasons.
  • Winter burn. Foliage keeps losing water on bright windy winter days while frozen roots cannot replace it. Shows on the windward and sunny sides, often with a sharp line at old snow level.
  • Waterlogging. Arborvitae will not tolerate a root zone that stays saturated. Browning from the bottom up on heavy ground points here.
  • Root damage or girdling from planting too deep, a tight wire basket left on, or trenching work nearby.

The brown will not turn green again

Arborvitae regenerate poorly from old bare wood. A branch cut back past all its green foliage usually stays a gap permanently. Trim dead material back only to where live green begins, and let the plant fill in from the tips over one to three seasons.

What to do with a plant that passes the scratch test

  1. Water deeply — slowly, at the root zone, enough to wet the whole root ball.
  2. Mulch 5–8 cm / 2–3 in deep, kept clear of the trunk itself.
  3. Do not feed a stressed plant. Fertiliser pushes growth that struggling roots cannot support.
  4. Shake or brush out the dead inner foliage so light reaches the live growth.
  5. Wait a full growing season before deciding. Recovery is measured in seasons, not weeks.

Common questions

How can I tell if my arborvitae is dying?

Scratch a small patch of bark on a branch with a thumbnail. Green or pale greenish-white underneath means that branch is alive, whatever the foliage looks like; dry brown or tan underneath means it is dead. Work from the outer twigs inward, then test the trunk near the base — a live trunk with dead branch tips is a recoverable plant, while a trunk that scratches brown at the base is not. Also look at where the brown sits: inner browning near the trunk is normal seasonal shedding, while brown at the tips and outer edges is a problem.

Is it normal for arborvitae to turn brown inside?

Yes, and it alarms a lot of people every autumn. Arborvitae shed their oldest foliage, which is the growth closest to the trunk, in late summer and autumn. You get a band of orange-brown inside the plant while the outer surface stays green, and the dead foliage drops or can be shaken out. Normal shedding is always inner and the outer tips stay green — the reverse pattern, green inside and brown at the tips, is the one that signals trouble.

Will a brown arborvitae turn green again?

The brown foliage itself will not. Arborvitae have very little capacity to regenerate from old bare wood, so a branch that has gone fully brown generally stays bare even if the plant survives. What recovers is the plant as a whole — if the scratch test shows live wood, new growth comes from the tips and from any remaining green foliage, slowly filling in over one to three seasons. Gaps cut back to bare brown wood usually stay gaps permanently.

What is winter burn on arborvitae?

Foliage browning caused by water loss in cold weather. The leaves keep transpiring on bright, windy winter days while the roots are in frozen ground and cannot replace the water, so the exposed foliage dries out and goes orange-brown. It shows up on the windward and sunny sides, often with a sharp line at the snow level where buried foliage stayed protected. It looks dramatic and is usually survivable — scratch test before writing the plant off.

How much water does a new arborvitae need?

Deep, regular watering through the first two growing seasons, roughly weekly in the absence of rain and more often in heat, aiming to wet the whole root ball rather than the surface. Most arborvitae that die in their first two years die of drought, and the symptoms lag weeks behind the dry spell that caused them. Established plants are reasonably tolerant but still brown in sustained drought, particularly those in a hedge competing with each other.

Can you cut dead branches off an arborvitae?

You can remove dead wood at any time, and it tidies the plant, but do not expect the gap to fill. Arborvitae do not reliably produce new shoots from old wood with no green on it, so cutting a brown branch back to the trunk leaves a permanent hole. Trim dead material back only to the point where live green foliage begins, and accept the shape you are left with while new growth extends from the tips.

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