Thuja occidentalis (Aurea Group)
Common Name: American arborvitae
Type: Needled evergreen
Family: Cupressaceae
Zone: 2 to 7
Height: 2.00 to 45.00 feet
Spread: 1.00 to 30.00 feet
Bloom Time: Non-flowering
Bloom Description: Non-flowering
Sun: Full sun to part shade
Water: Medium
Maintenance: Low
Suggested Use: Hedge
Leaf: Evergreen
Other: Winter Interest
Tolerate: Clay Soil, Black Walnut, Air Pollution

Culture

Grow in average, medium moisture, well-drained soils in full sun to part shade. Somewhat wide range of soil tolerance, but prefers moist, neutral to alkaline, well-drained loams. Intolerant of dry conditions. Best in full sun, but generally appreciates some light afternoon shade in hot summer climates such as the St. Louis area. Avoid full shade where foliage density will substantially decrease. Avoid exposed, windy sites.

Noteworthy Characteristics

Thuja occidentalis, commonly known as American arborvitae, is a dense, conical to narrow-pyramidal (sometimes maturing to broad-pyramidal), often single-trunked, evergreen tree that is native to eastern and central Canada south to northern Illinois, Ohio and New York with scattered populations further south in the Appalachians to North Carolina. Species trees will grow to 60’ tall. Over 300 cultivars have been selected over the years, and differentiating between selections has become extremely difficult. Aurea Group plants are basically forms that feature yellow foliage, ranging from trees (e.g., T. occidentalis ‘Douglasii Aurea’ -- narrow pyramidal to 45’ tall) to dwarf forms (e.g., T. occidentalis ‘Aurea’ – globose to 2’3’ x 2-3’). Seed cones, if present, are not particularly showy. Arborvitae means tree of life.

Problems

No serious insect or disease problems. Leaf blight may cause some foliage to spot and drop. Watch for canker. Leaf miner may damage leaf tips. Bagworms, mealybugs, scales and spider mites are occasional visitors. Foliage may show some winter burn (turns yellow-brown) in exposed sites. Susceptible to damage/stem breakage in winter from ice and snow accumulations.

Garden Uses

Use depends upon form. Taller plants make good screens. Dwarf plants make good foundation plants, hedges or edging.