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Arborvitae Vs. Juniper

Junipers (Juniperus spp.) and arborvitae are both part of the cypress (Cupressaceae) plant family, but juniper species are part of the genus juniperus, which is a large genus of evergreen shrubs, trees and groundcover, while arborvitae species are part of the smaller genus, thuja, which consists of conifer trees and shrubs. Each is prized by home gardeners for a variety of reasons, but which tree is right for your landscape depends on the planting location and use, as well as the level of maintenance you prefer.
  1. Appearance

    • Arborvitae species are coniferous, typically producing scaly, diamond-shaped needles that give off a pleasant fragrance. Foliage colors include yellow, bluish and shades of green. Juniper foliage may be either scalelike or needlelike, and these different forms may be mixed on the same branch, or on separate branches. Arborvitae and juniper fruit are both berrylike but they’re really round cones. Arborvitae cones are covered with thick scales, while juniper cones appear leathery. Some junipers produce fruit that turns blue when mature, while others turn red or coppery. Juniper trees also have a strong fragrance.

    Growth

    • Arborvitae species mature to heights of about 40 to 50 feet, and grow in a dense, pyramidal shape. However, there are cultivars that range in size and form, including dwarf cultivars and species that grow in a rounded shape instead of pyramidal. Junipers are more varied than arborvitae, and range from evergreen woody plants that spread as groundcovers to species that grow upright in a tree or shrub form. Juniper groundcovers grow in a vining habit, while shrubs have a spreading, sideways oval growth habit, growing wider than they grow tall. Upright shrubs and trees grow in columnar, slender pyramidal or oval shapes.

    Culture and Maintenance

    • Arborvitae plants thrive in fertile, moist, well-drained soil and do best in full sun. Hardiness varies depending on the cultivar, but typically ranges between U.S. Department of Agriculture plant hardiness zones 2 and 7. They tolerate light shade, but tend to become leggy when growing in full shade. Arborvitaes tolerate acidic and alkaline soils, and while they tolerate pruning, it’s rarely required. Junipers also vary in hardiness depending on species, ranging between USDA zones 3 and 9. They share many of the cultural requirements that arborvitae thrive in, including moist, well-drained soils in full to partial sun, but are also extremely tolerant to urban environments. They’re particularly tolerant of poor soils, compacted soils, various pH levels, and heat and drought. Junipers will not tolerate full shade or soggy sites. Shrub and spreading junipers tolerate frequent pruning, and are often pruned to control their size and shape.

    Landscape Use

    • Arborvitaes and junipers both have dense foliage, making them useful as hedges or screen plantings. Dwarf arborvitae cultivars also make attractive rock garden specimens. The rapid growth and low cost of arborvitaes make them preferable for foundation plantings and specimens, but their aesthetic appeal may be limited to spring and summer months. During the fall and winter, some species of arborvitae turn brown. Junipers offer a wide range of growth habits, size and foliage colors, and can serve many functions depending on species and cultivars. Ground cover species fill in bare spots and shrubs make ideal foundation specimens and mass plantings. The fine texture and thick density of the tree forms are also ideal as specimen plants or as a focal point in your landscape.