Thuja occidentalis is a native species commonly known as cedar, as common cedar, or as white arborvitae. It is undoubtedly theconifer mostly used in the making of high and dense hedges. Its green foliage will pale during winter, and its growth is rapid. Optimal conditions will allow a growth of 30 to 60 cm per year, once rooted. The roots are spread out, very fibrous and shallow. At full maturity, it can reach up to 12 to 18 m in height. An annual trim is thus necessary and will ideally be performed during summer. The Thuja occidentalis is hardy in zone 2.
Thuja occidentalis ‘Nigra’ is a hybrid variety derived from eastern white cedar (Thuja occidentalis). This cultivar is popular for its appearance which remains dark green even during dormancy. Its habit is similar to the one of the white cedar, and is also mainly used in the making of hedges. Although smaller in size than white cedar, the eastern black cedar can reach up to 6 m in height, and to 3 m in width. An annual trim is therefore necessary. It should be noted that the ‘Nigra’ is more likely to produce seeds than is the white cedar.
Thuja occidentalis‘Brandon’ has narrow and columnar shape. Its growth is considered average and its foliage is thick and very dense. When reaching maturity, Thuya occidentalis ‘Brandon‘ can reach up to 6 m in height. It is used in the making of high hedges, or is rather planted in isolation. Hardy up to zone 3, it does not tolerate shade very well, just like most cedars. Its fibrous roots make transplanting quite easy. Like ‘Fastigiata compacta’, it is an ideal selection for planting in a small yard. Although trimming ‘Brandon’ seems quite easy, it remains somehow unnecessary for the well-maintenance of this cultivar’s properties.
Thuja occidentalis ‘Emerald’ is renowned for its bright green foliage. It is usually planted in isolation, but can also be planted in hedgerows. ‘Smaragd’ is planted in zone 5 in order to maintain its ornamental appearance, or in zone 4 – although protection against winter browning may be required. It tends to thin out more easily than other cedar varieties when placed within the shade, and hardly regenerates after having been damaged by wind, by the lack of light, or because of a severepruning. Besides, trimming is not necessary.
Thuja occidentalis ‘Holmstrup‘ has a compact and conical shape. It is a slow-growing variety that remains small with a maximum growth of about 3 m in height and 1 m in width. Holmstrup ‘deserves to be better known as it is hardy until zone 2b: it is a variety of pyramidal cedar that would be preferred if you live north of Montreal. It is generally used for a focal point and mass planting but can also be used as a screen when planted in hedge. Trimming is not necessary.
‘Yellow Ribbon‘ white cedar has a pronounced conical shape. It is very trendy and is mainly used as a showpiece plant in modern landscaping. Famous for its lime green ribbon at the tips of the leaves, it is particularly suited to the style of newly built homes in darker shades such as brown or black. Planted in hedges, Yellow Ribbon is breathtaking! It is hardy and hardy to the zone. No pruning is required. Growth is medium.