Shrubs are woody-stemmed perennial plants that emerge from multiple stems at their bases. What distinguishes shrubs from trees is that shrubs do not grow from one trunk. The multiple stems and branches give shrubs a full-bodied appearance. Small shrubs grow less than 4 feet tall and function well as groundcovers. Medium shrubs grow between 4 and 6 feet tall and function as landscaping accents. Large shrubs grow over 6 feet tall and add height to your landscaping design.
Evergreen shrubs maintain their foliage and color year-round. There are two categories of evergreen shrubs---broadleaved shrubs and narrow-leaved shrubs. According to the Colorado State University Extension, the larger the leaf the higher its moisture requirements are.
Evergreen shrubs have year-round foliage and color. Although evergreen shrubs do lose some of their leaves every year, the shrubs are never bare and maintain a full appearance.
Some narrow-leaved evergreen shrubs include eastern arborvitae (Thuja occidentalis), savin juniper (Juniperus sabina) and eastern white pine (Pinus strobus). Broadleaved evergreen shrubs include Korean boxwood (Buxus microphylla), emerald gaiety (Euonymus fortune) and Rhododendron species.
In the warmer seasons, deciduous shrubs add varying textures, colors and shapes to the landscape. Some shrubs bloom and produce fruit. Deciduous shrubs lose their foliage in the fall. Their exposed stems and branches add landscaping beauty with their forms, colors and textures.
Some deciduous shrubs include Kelsey dogwood (Cornus sericea), St. John's wort (Hypericum kalmianum), black chokeberry (Aronia melanocarpa), flowering quince (Chaenomeles speciosa) and serviceberry (Amelanchier spp.)
Purpose in Landscaping
Use shrubs in landscape designs to soften the hard architectural lines of buildings and houses. When placed in close to a structure, they act as insulation, barriers to wind and sound and as providers of privacy.
Shrubs function as a landscaping building block. They instantaneously transform a bare area into a well-manicured garden. Tall shrubs add height and depth to a planting arrangement. Use low-growing shrubs as fillers and groundcovers.
The breadth of shrubs makes it possible to delineate sections of the landscape with walls of shrubbery once the leaves and branches of neighboring shrubs become intertwined.
Wildlife use shrubs as homes because of their dense, multibranched structures. The inner branches of shrubs do not receive as much sunlight as those on the periphery. Birds, squirrels, insects and other animals will quickly take shelter in a shrub for shade and protection.