Eastern Arborvitae

New growth flush

Thuja occidentalis

Cupressaceae · coniferous tree · introduced

Last updated

Eastern arborvitae (American arborvitae) is a conifer native to eastern and central North America. It reaches 40 ft with a conical form, fine foliage texture, and brown cones. It has reddish-brown bark fissured into narrow ridges and grows as a single-stem tree.

Eastern arborvitae is hardy in zones 4a-9b and tolerates sun to part shade with wet-tolerant, alkaline soils (pH 5.2-7.0). It grows slowly with low maintenance and is notably tolerant of clay, wet soil, and urban conditions. The essential oil in foliage is poisonous if ingested in large doses.

Plant Profile

Size & Form

Height
40 ft
Spread
16 ft
Growth Rate
Slow
Size at 20 yr
25 ft
Lifespan
Long-lived

Site Requirements

Light
Sun to Part Shade
Soil Drainage
Wet Tolerant
Soil pH
5.2-7.0
Water
Moderate
Drought Tolerance
Low
Hardiness
Zones 4a–9b

Ornamental Interest

Bloom Time
Non-flowering
Origin
USDA Zone (2)3 The species is native from eastern to

Field Observations

Eastern Arborvitae 'Smaragd' new growth
Eastern Arborvitae 'Smaragd': New growth
April 23, 2026 · Issaquah
Watch for this season
Scale insectHigh

Crawler Emergence

Phytophthora Root RotModerate

Growing Season Stress Expression

Twig BlightModerate

Canker Development and Twig Dieback

LeafminerModerate

Larval Mining

+ 1 more — see full disease and pest lists below

Diseases: Regionally Documented (13)

Pests: Regionally Documented (10)

Phenological Calendar

As of June 3, 2026, Puget Sound stations range from 2435.5 to 2672.8 GDD₃₂. Eastern Arborvitae has passed new growth flush (1596 GDD₃₂).

Regional Season Tracker

GDD₃₂ accumulation across 7 Puget Sound stations · as of Jun 3, 2026
Station GDD₃₂ Current Stage Next To Go
Issaquah / East King 2,673 New growth flush — —
Kent / Auburn 2,665 New growth flush — —
Seattle / UW 2,610 New growth flush — —
Olympia / Tumwater 2,570 New growth flush — —
Tacoma / Puyallup 2,535 New growth flush — —
Bellingham / Whatcom 2,533 New growth flush — —
Sequim / Rain Shadow 2,436 New growth flush — —
View full calendar (5 stages)
Stage GDD32 Typical Window
● New growth flush BBCH 11 NOW 1596 Observed Feb 15-Mar 15
Pollen release BBCH 61 — Apr 1-Apr 30
Pollen shed complete BBCH 69 — Apr 15-May 15
Cone development BBCH 71 — Jun 1-Aug 31
Cone maturity and seed shed BBCH 85 — Sep 1-Nov 30

Source: Field observation, Issaquah, WA, 2026-04-23 About GDD₃₂ →

Season tracker for Kent / Auburn as of Jun 3, 2026. Predicted dates use 16-day weather forecast through Jun 19, 2026, then climate normals.

Cultivars (5)
'Golden Globe'
Common name: Golden Globe Arborvitae; Mature height: 3–5 ft
Hardy to USDA Zone 3
'Hetz Midget'
Common name: Hetz Midget Arborvitae; Mature height: 3–4 ft
Hardy to USDA Zone 3
'Rheingold'
Common name: Rheingold Arborvitae; Mature height: 4–5 ft
Hardy to USDA Zone 3
'Yellow Ribbon'
Common name: Yellow Ribbon Arborvitae; Mature height: 8–10 ft
Hardy to USDA Zone 3
Thuja occidentalis 'Smaragd' – new growth
'Smaragd'
Data Maturity
Structured Multiple sources. Expert review underway.