American arborvitae (Thuja occidentalis 'Degroot's Spire')

Overview

Thuja occidentalis ‘Degroot’s Spire’ offers a strikingly narrow, upright profile highly valued in contemporary landscape design. This dense, slow-growing cultivar of the native American arborvitae fits gracefully into tight spaces where broader evergreens overwhelm. Gardeners appreciate its medium green, twisted, scale-like foliage that holds its color well through the seasons.

As a needled evergreen, this cultivar of American arborvitae delivers year-round structure and texture. It is remarkably adaptable across a wide range of conditions, known for its low maintenance needs once established. The inherent resistance of Thuja occidentalis ‘Degroot’s Spire’ to certain environmental stresses makes it a reliable choice for foundation plantings or formal screening.

The ultimate benefit of planting Thuja occidentalis ‘Degroot’s Spire’ lies in its architectural form. Achieving heights of 20 to 30 feet while keeping a spread of only 4 to 6 feet makes it an indispensable plant for vertical accents, narrow screens, or formal axis points in the garden layout.

Fast Facts

• Plant Family: Cupressaceae
• Plant Type: Needled evergreen
• Hardiness Zones: USDA Zones 2-7
• Size at Maturity:
  • Height: 20-30 ft
  • Spread: 4-6 ft
• Bloom Time: Non-flowering
• Bloom Description: Non-flowering
• Sun Exposure: Full sun to part shade
• Water Needs: Medium
• Maintenance Level: Low

How to Grow

Planting Thuja occidentalis ‘Degroot’s Spire’ is best done in spring or fall to allow the roots to establish before temperature extremes. Locate specimens in sites receiving full sun, though light afternoon shade is beneficial in the hottest summer climates. While tolerant of various soils, this American arborvitae thrives best in moist, neutral to alkaline, well-drained loams.

Watering requirements for this evergreen are medium; ensure consistent moisture, particularly during the first few seasons after planting. Thuja occidentalis ‘Degroot’s Spire’ is intolerant of dry conditions, so deep, infrequent watering is preferable to light sprinkling. Fertilization is generally unnecessary unless the soil is extremely poor; if necessary, apply a slow-release evergreen food early in spring.

Pruning requirements are minimal due to its naturally tight, pyramidal habit. Avoid heavy shearing, as this can expose the interior wood. If site conditions are very exposed or windy, the branches may be susceptible to breakage from heavy ice and snow accumulation; careful winter placement planning is advised. Avoid planting in areas of full shade, which significantly diminishes foliage density.

Landscape Uses

The unique, attenuated form of Thuja occidentalis ‘Degroot’s Spire’ makes it an exceptional specimen or accent plant. Its strong vertical line draws the eye upward without consuming excessive horizontal space, contrasting beautifully with mounding perennials or broad shrubs. Use it sparingly for formal structure in rock gardens or clustered near entrances.

This cultivar excels as a narrow hedge where standard arborvitae varieties would grow too wide too quickly. Because it maintains a small footprint (only 4-6 ft wide), it serves perfectly as a tight screen along property lines or bordering utility areas. Consider using several in sequence to create a dramatic, architectural border effect.

When pairing companions, select plants that prefer similar medium moisture and full sun to part shade conditions, such as hardy ornamental grasses or mid-sized evergreen shrubs that offer textural contrast to the fine foliage of the American arborvitae.

Standout Features

Noteworthy Characteristics

Thuja occidentalis, commonly known as American arborvitae, Eastern arborvitae, Eastern white cedar or Northern white cedar, 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. Mature trees may reach 40-60’ tall in the wild over time, but in cultivation typically grow much smaller to 20-30’ tall. Scale-like, aromatic, yellow-green to green foliage appears in flattened sprays. Red-brown bark will exfoliate on mature branches and trunks.The common name of arborvitae (tree of life) comes from early French settlers to North America who learned from Native Americans that the tree’s foliage could be used to treat scurvy.‘Degroot’s Spire’ is a dwarf, slow-growing cultivar with an upright, pyramidal habit. Features twisted, scale-like, medium green foliage. Can reach 15-20 feet tall and 4-5 feet wide in 15-20 years

Tolerances

• Clay Soil
• Black Walnut
• Air Pollution

Potential Problems

Foliage issues can manifest as leaf blight, causing spotting and drop, or leaf miner damage targeting the leaf tips. Inspect plantings regularly for common pests such as bagworms, mealybugs, scales, and spider mites, treating promptly if infestations become heavy. A common cosmetic issue is winter burn; foliage turns yellow-brown in exposed sites where winter winds intensify dehydration.

Management of potential issues relies heavily on proper siting. Planting Thuja occidentalis ‘Degroot’s Spire’ away from harsh prevailing winter winds reduces the incidence of winter burn. Ensuring excellent drainage minimizes the risk of root stress which can invite canker. Vigilant monitoring helps catch pest or disease issues before they heavily impact the plant’s dense form.

Frequently Asked Questions

What hardiness zones is American arborvitae suitable for?

Thuja occidentalis ‘Degroot’s Spire’ is exceptionally cold-hardy, thriving across USDA Zones 2 through 7.

How large does Thuja occidentalis ‘Degroot’s Spire’ grow?

This cultivar reaches mature heights between 20 and 30 feet tall, maintaining a relatively narrow spread of 4 to 6 feet wide.

What sun exposure does American arborvitae need?

For best density and color, this evergreen requires full sun, although it can tolerate part shade, especially during intense summer heat.

When does American arborvitae bloom?

As a coniferous evergreen, Thuja occidentalis ‘Degroot’s Spire’ is non-flowering.

Conclusion

Thuja occidentalis ‘Degroot’s Spire’ is an outstanding choice for gardeners needing vertical screening or formal accents with minimal space requirements. Its low maintenance nature and tolerance for challenging conditions, including clay soil, confirm its reliability as a landscape workhorse American arborvitae. Before installing, confirm your local site conditions fall within USDA Zones 2-7 and ensure adequate moisture availability.

Designing with Vertical Elements

When integrating vertical evergreens like Thuja occidentalis ‘Degroot’s Spire’ into a landscape plan, think about the eye path. These narrow forms act like natural arrows, guiding visitors through the garden or breaking up overly horizontal sightlines. Place them strategically along boundaries or to anchor the corners of foundational plantings for strong architectural definition that lasts all year.

To enhance the architectural look, utilize contrasting textures nearby. Pairing the fine, scale-like foliage of this American arborvitae with broader leaf hostas, textured ornamental grasses, or coarse-barked deciduous trees creates dynamic visual interest across the seasons. This contrast emphasizes the spire shape of the Thuja even further.

Companion Planting Considerations

Because Thuja occidentalis ‘Degroot’s Spire’ prefers medium moisture and tolerates urban air pollution well, choose companions that share these general needs rather than strict soil chemistry requirements. Plants that thrive in similar filtered light conditions, such as certain Hydrangeas (like Hydrangea paniculata varieties) or established shade perennials like Astilbe or Helleborus, make excellent neighbors offering seasonal bloom beneath the evergreen canopy.

Avoid placing shallow-rooted, highly drought-tolerant perennials directly against the base of your Thuja, as this can lead to competition for the critical medium water supply this plant requires. Keep planting beds mulched to retain the necessary soil moisture and moderate soil temperatures around the root zones of the American arborvitae.