The Arbor Day Foundation describes various reasons tall hedges that are used for privacy. Blocking sound and sight are the main uses for tall hedges. Determining the height you want will help determine the type of hedge. Popular trees used for hedges grow upwards of 40 feet. Popular shrubs, such as Arborvitae, range from 10 to 30 feet high. The foundation also suggests looking into flowering shrubs for color.
Evergreens are among the most used plant for privacy. Both leafy evergreens and conifers are used. Boxwoods and holly can grow upwards of 20 feet or higher. Virginia Tech lists the Southern Magnolia, American Holly and Fosters Holly as examples of leafy evergreens. Purdue University adds to the list trees with colorful leaves such as Japanese Barberry with red leaves and White Fir with a silver-green to blue color. Purdue also suggests varieties such as Little Linden, Canada or Carolina Hemlock.
Evergreens can grow to heights of 80 feet. Examples of evergreen trees used as hedges include Norway Spruce, Eastern White Pine, Douglas Fir and White Fir. Each of these, when planted close together, grow into solid formations blocking sound, sight and wind.
Not all shrubs are the pruned evergreens commonly seen. Deciduous shrubs grown for privacy also have blooms and are scented. The Rose of Sharon is an example of a flowering shrub having white, pink or red flowers during the summer and fall. The bush can grow to 12 feet. The Chinese Lilac offers rose-purple flowers in May and grows to 8 feet. Various cranberry bush varieties provide white flowers in May or June with red fruit in autumn. These bushes range from 6 to 15 feet.
Successful use of hedge plants requires an understanding of the width of space available. Emerald Arborvitae grows up to 4 feet wide, but American Arborvitae reaches 15 feet in width. Boxwoods attain a girth of 6 feet. Once you know the spacing, understanding the required spacing for the hedge plant is next. Junipers and cedars require 6 to 8 feet of space between trees; pines and spruce require as much as 12 feet between trees. The Arbor Day Foundation reminds growers to measure from the center of the plant when determining the distance between plants. Remember, too, that plants grown close together do not obtain the same height and width as similar varieties found in the wild or standing alone.