Thuja Emerald Four Ball 20 Litre Pot 125-150cm High

Thuja occidentalis 'Smaragd' – Emerald Green Arborvitae
Thuja occidentalis 'Smaragd' is a slow-growing, narrowly columnar evergreen conifer and one of the most elegant and refined hedging and specimen plants available to UK gardeners. Producing dense, flat sprays of rich, jewel-bright emerald-green foliage that hold their vivid colour with exceptional consistency through every season, 'Smaragd' delivers year-round structure, beauty, and privacy with effortless grace. Its naturally neat, pencil-slim silhouette and restrained rate of growth make it an outstanding choice for formal hedges, defined garden boundaries, and architectural accent planting where precision and polish are the priority.

Fully hardy, undemanding in its soil requirements, and requiring very little maintenance to remain looking immaculate, Thuja 'Smaragd' is as practical as it is handsome. Whether used as a crisp formal hedge, a symmetrical pair framing an entrance, or a bold vertical accent in a structured planting scheme, it is a thoroughly rewarding plant that offers exceptional ornamental value season after season with only the lightest attention.

Habit & Appearance

Form and foliage. 'Smaragd' develops a slender, tightly upright, columnar to narrowly conical form that remains naturally well-defined and architectural as the plant matures, holding its shape beautifully without any intervention. The foliage is carried in neat, flat, overlapping sprays of fine, scale-like leaves with a pleasantly smooth texture and a gentle, resinous fragrance when brushed or trimmed. Where 'Smaragd' truly distinguishes itself from other conifers is in the extraordinary consistency of its foliage colour: the rich, glowing emerald-green for which it is named holds with remarkable reliability through all four seasons, resisting the bronzing and dulling that affects many comparable conifers in cold weather. Even through the harshest winter months, plants maintain a fresh, vibrant, well-kept appearance. Left to grow freely at maturity, 'Smaragd' will typically reach around 3–4 metres in height, making it an inherently manageable plant that rarely outgrows its allotted space.

Growth rate. 'Smaragd' is a slow to moderately growing conifer, typically putting on around 15–20 cm of new growth per year under good conditions. While this means it takes longer to establish full height and coverage than more vigorous hedging alternatives, its naturally dense, compact branching habit means that even younger plants contribute meaningful structure and screening, and its restrained pace of growth is precisely what makes it so low-maintenance and long-lived in the garden.

Growing Conditions

Position. Thuja 'Smaragd' performs best in a position that receives full sun to partial shade. It thrives in an open, bright aspect and produces its most vibrant foliage colour in good light, but it tolerates dappled shade well, making it a versatile option for planting alongside walls, fences, or established trees. Fully hardy throughout the UK, it copes comfortably with cold winters and shows reasonable tolerance of moderately exposed sites, though it is best sited away from the most severe coastal winds or exceptionally exposed and windswept locations where foliage scorch can become an issue.

Soil. Adaptable to most fertile, reasonably well-drained soils, including clay, loam, and sandy ground. Like other Thuja, 'Smaragd' tolerates moderately moist conditions better than many conifers but will not perform well in permanently waterlogged or poorly drained soil. On heavier ground, incorporating organic matter and improving drainage at planting will encourage stronger, healthier establishment. A slightly acid to neutral soil pH is ideal, though 'Smaragd' performs well in mildly alkaline conditions too.

Planting spacing. For a dense, formal hedge with clean, defined lines, plant approximately 50–60 cm apart. This spacing will allow individual plants to knit together into a continuous, well-filled screen without overcrowding. For use as specimen accent plants or to create symmetrical pairs or avenues, allow generous space for each plant to develop its naturally elegant columnar form without competition from neighbouring plants.

Care

Watering. Water regularly and thoroughly during the first full growing season after planting to support strong and healthy root establishment. This is particularly important during dry spells in spring and summer, when newly planted conifers are most susceptible to moisture stress. Once well established, Thuja 'Smaragd' develops a good degree of drought tolerance and will generally require supplementary watering only during prolonged dry periods.

Feeding. Apply a balanced, slow-release granular fertiliser in early spring each year to support healthy, consistent growth. A fertiliser formulated for conifers or hedging plants is particularly well suited to this purpose. Mulching around the base of plants each spring with bark chippings or garden compost will help to conserve soil moisture, suppress competing weeds, and moderate root temperature through the growing season and into winter.

Pruning. One of 'Smaragd's' most celebrated qualities is its naturally immaculate, self-tidying form, which requires minimal trimming to remain looking its best. For plants used as specimens or accent features, no pruning at all may be necessary, as the plant's inherent structure is a significant part of its appeal. Where a formal hedge is being maintained, a single light trim in late summer is usually sufficient to keep the outline crisp and well-defined. Always avoid cutting back hard into old, bare wood, as Thuja does not regenerate readily from stems that have lost their foliage. Light, careful trimming carried out with sharp tools consistently produces the neatest and most attractive long-term results.

Ideal Uses

• Formal hedging and boundaries – Naturally neat and columnar, 'Smaragd' produces beautifully crisp, refined hedges that require