American arborvitae
Thuja occidentalis
A dense, conical-to-narrow-pyramidal evergreen tree native to eastern and central North America, prized as a screening and foundation conifer. Flat, fan-like sprays of scale-like, aromatic yellow-green foliage clothe the tree from the ground up, and red-brown bark exfoliates on mature trunks. Wild trees can reach 40 to 60 feet but cultivated plants typically stay near 20 to 30 feet; small urn-shaped cones and dense evergreen cover make it valuable food and shelter for birds.
Native: 22 US states + 6 CA provinces
Climate fit: broad (82/100)
Structure
Focal point
Border
Light
Full sun / Part sun / Part shade
Water
Consistent moisture
Mature size
20-40 ft tall · 5 ft apart
Hardy in zones
2a-7b
brutally cold to cold winters
AHS heat range
1-9
Plant range authored in AHS heat-zone terms.
Native in Illinois
Yes
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Native across 28 US states and Canadian provinces - a wide-ranging part of North America's plant communities.
Cold hardiness
These values are location-based: this location's current hardiness is the baseline, and the 2050 value is a projected future climate for this same location.
Now
Zone 6b
Plotwright
USDA Zone 6b
-5°F to 0°F
Well-suited
Zone 7a
Plotwright
0°F to 5°F
Well-suited
In plain terms: This location has cold winters. Its winters are projected to keep warming through 2050.
✓
Well-suited today and still thriving in 2050.
Heat tolerance
Heat tolerance values are location-based too: heat days today are observed at this site, and the 2050 value projects this same location under a future climate.
Loading AHS heat-zone data for this location...
Where this plant fits
Suitable across 35 ecoregions - 30 climate-resilient through 2070 · 5 suited today. Best matches first.
Similar plants
Browse lateral options with similar roles, light needs, size, or native-range overlap; these are not filtered for a better climate fit.
Educator packet
Plant packet
American arborvitae educator packet
A dense, conical-to-narrow-pyramidal evergreen tree native to eastern and central North America, prized as a screening and foundation conifer. Flat, fan-like sprays of scale-like, aromatic yellow-green foliage clothe the tree from the ground up, and red-brown bark exfoliates on mature trunks. Wild trees can reach 40 to 60 feet but cultivated plants typically stay near 20 to 30 feet; small urn-shaped cones and dense evergreen cover make it valuable food and shelter for birds.
Scientific name
Thuja occidentalis
Plant type
tree
Hardiness
2a-7b
Light
full-sun, part-sun, part-shade
Moisture
consistent
Spacing
60 inches
Classroom prompts
- Which plant traits are observations, and which are care recommendations?
- How would this plant fit change if the garden location moved warmer, colder, wetter, or drier?
- Which source-backed facts would you cite in a lesson handout?
Use the Sources & citations section below for page citation styles and the field-level source list.
Sources & citations
Cite this page
For lesson plans, articles, or research that uses this page. Use the source cards below to explore the references that informed this record.
Plotwright. (2026, May 17). American arborvitae (Thuja occidentalis). Retrieved 2026, August 20, from https://plotwright.com/plants/thuja-occidentalis
Sources used for this record
This record is compiled from the sources below.
Lady Bird Johnson Wildflower Center Native Plant Database
Botanical research database





