The Emerald Green Arborvitae, Thuja occidentalis ‘Smaragd’, is a highly popular evergreen conifer used in residential and commercial landscapes. This specific cultivar is favored for its naturally narrow, conical growth habit, which allows it to fit into tighter spaces than many other screening plants. The deep, rich emerald green color of its scale-like foliage remains vibrant throughout the year. This makes it an excellent choice for creating year-round privacy screens or as a formal vertical accent.
Understanding the Mature Dimensions
The question of how tall the Emerald Green Arborvitae gets is answered by its genetic programming as a semi-dwarf cultivar. Under typical growing conditions, this plant reaches a mature height ranging from 10 to 15 feet. In ideal environments, the plant may occasionally push the upper limit, reaching up to 16 feet.
The mature width is a defining characteristic of this narrow variety. The typical spread is quite compact, generally settling between 3 and 4 feet wide. This slim profile is what makes it so suitable for planting in rows to create a dense, space-saving hedge.
The term “mature dimensions” refers to the size the plant attains after a significant period of development, usually around 10 to 15 years post-planting. While the plant continues to grow slowly beyond this timeframe, the rate of height gain drastically decreases. Understanding this final size is important for landscape planning to ensure the tree does not outgrow its intended space or interfere with structures.
How Fast Does it Grow
The Emerald Green Arborvitae is categorized as a medium-to-slow growing evergreen. This characteristic contributes to its dense form and low-maintenance appeal. The average annual vertical growth rate for an established plant typically falls between 6 and 12 inches per year. This moderate pace means it will take several years for a young specimen to reach its full privacy screening height.
In comparison to faster-growing conifers, this slower rate results in denser branching. This helps the plant maintain its tight, columnar shape without much intervention. Growth is usually fastest during the plant’s juvenile years, provided it has ideal conditions, such as sufficient water and sunlight. As the arborvitae approaches its mature height, the annual growth rate naturally begins to slow down significantly.
Site Conditions That Affect Final Size
The final height and overall vigor of an Emerald Green Arborvitae are heavily influenced by the conditions of its planting site. Optimal growth occurs when the plant receives full sun, meaning at least six hours of direct sunlight daily. Planting in partial shade is tolerated, but too much shade can lead to sparse foliage and a less robust final size.
Soil quality and moisture levels are also significant factors controlling the plant’s development. A rich, well-draining soil that retains consistent moisture encourages the most vigorous growth. This helps the plant reach the higher end of its size potential.
Conversely, plants subjected to prolonged drought stress, poor soil, or planting sites with excessive competition will often have stunted growth. They may not achieve their full mature dimensions.
Controlling Height and Shape Through Pruning
While the Emerald Green Arborvitae has a predictable natural shape, its size can be managed through strategic pruning. Once the plant nears the desired maximum height, the growing tip, or apical meristem, can be removed to halt vertical growth. This action will encourage the plant to focus its energy on lateral growth, resulting in a slightly wider and denser form over time.
Pruning should always be light and consistent, avoiding cuts into the brown, interior wood where no green foliage remains. Arborvitae does not regenerate growth from old wood, so cutting too deep will create permanent bare patches. The best time for shaping and height maintenance is from early spring through mid-summer. This allows the plant time to harden off new growth before the winter. To maintain a tight shape, trim only the tips of the branches, removing no more than 20% of the total foliage at any one time.