The blue Atlas cedar (Cedrus atlantica var. glauca) is loved for its feathery sea foam or blue-green foliage. Because it will reach a height of 50 feet and a spread of 30 to 40 feet, refrain from planting expensive or singular specimen shrubs within 20 feet. Expendable, massed groundcover-like shrubs are ideal, clothing the area under the cedar until it grows over them.
Small-sized specimens of blue Atlas cedar are typically planted from containers or in balled-and-burlapped roots. Thus, there may be an urge to plant shrubs and other plant materials around the cedar, not taking into account the tree's future size. Over the course of 4 to 8 decades, the blue Atlas cedar will slowly but elegantly stretch its boughs across a planting bed.
From a design standpoint, this cedar is planted as a specimen, a singular plant allowed to grow uncrowded and unimpeded into a magnificent focal point. Crowding the architecturally interesting tree detracts from its beauty and can cause some branches to become unnecessarily shaded and denuded of needles.
In all cases, plants in the vicinity of a blue Atlas cedar should have similar growing requirements, including soil pH and watering needs. Do not plant shrubs in the root zone of the cedar that need vastly different watering, fertilizing or climatic conditions.
Consider planting inexpensive, massed shrubs within the 20-foot radius around the blue Atlas cedar or allowing the tree to grow in a carpet of turfgrass. Low-growing shrubs--those that stay under 4 feet in mature height--are recommended. Mass the shrubs around the tree so that they visually anchor the cedar tree but do not shade or block the horizontal growth of the tree branches. As the tree grows larger, its boughs will block out light and rainfall to the shrubs, killing them. Therefore, it is best to invest in inexpensive shrubs for a temporary, 10-to-20 year, planting display.
Other specimen trees or shrubs that are to be planted near the growing blue Atlas cedar should be planted no closer than 20 feet to the trunk. Such distance allows for both the cedar tree and the specimen shrub room to grow without encroaching on each other for several years, if at all.
Mature blue Atlas cedar trees--those that have reached a spread of over 35 to 40 feet--will likely not extend their lower branches any farther. Designing a planting bed filled with shrubbery is made easier in regard to plant spacing but also in terms of where to locate shrubs so they do not detract from or block the view of the large specimen tree's branches and shape.
Consider using shrubs that have contrasting foliage colors, such as a dark green, golden, or red/burgundy plants. Juxtapose these shrubs or small trees, and they will accentuate the cedar tree's bluish foliage. Avoid planting similarly textured conifer evergreens around the cedar, as they will be visually lost.