American Arborvitae

Thuja occidentalis

Family: CupressaceaeZones: 3a-7b

Landscape conifer
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Deer browse target

Pet & Human Safety

People: Hazard to peoplePets: Not on the ASPCA lists as we read them

Hazardous parts

No source found

Preparation

Not applicable. This plant is not a food crop

Hazard type

Not yet checked.

Hazard route

Not yet checked.

How complete this information is

We have not researched the safety of this plant yet.

Toxic to pets

No ASPCA entry found.

Genuinely not listed by either source checked. Not assumed safe or unsafe. Note: PlotAndPetal's separate Green Giant Arborvitae entry (a different Thuja hybrid) does have a documented horse-toxicity finding from NC State Extension: the two are not necessarily the same toxicity profile.

Patent / trademark

Many named cultivars exist and some may be patented, but this was not checked

PlotAndPetal cannot tell you whether a plant you found can be eaten. Only someone who can see the plant can identify it.

Poison control

If someone has collapsed, cannot be woken, is having a seizure or has trouble breathing, call 911 now. For any other possible poisoning, call Poison Help: 1-800-222-1222.

Emergency number source: U.S. federal law (47 U.S.C. § 251(e)(3)), read 2026-10-07.

Naturalist Lore

Historical Background & Breeding Lore

The history of this plant and its name, and how it was bred, where we have them.

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Care

Hardiness zones: 3a-7b.
Water needs: moist soil; high atmospheric moisture preferred; dislikes dry, exposed, or windy sites
Mature size: 40-60 ft tall, 10-15 ft wide; dense, pyramidal to conical habit, slow growth rate.
Where it comes from: Central and eastern Canada to north-central and eastern North America.

Soil & Drainage

Pruning & Flush Rhythm

Feeding Schedule

How to prepare the soil, when and what to feed, and how and when to prune where that applies.

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