Selecting Suitable Shrubs to Make Hedges
A "hedge" is a wall composed of plants. Some hedges are purely decorative, while others serve primarily a practical function. Hedge plants used decoratively are often trimmed to precise sizes and shapes and include evergreen and deciduous shrubs. Such hedge plants may also serve the practical function of affording a property some security. Almost any row of densely growing hedge plants will enhance security to some degree. If you need a higher level of security, but still wish to stick to hedge plants rather than fences, select a variety that has thorns, or at least prickly leaves.
But security is not the only practical function that hedges can serve. Hedge plants may also be used to create privacy screens or windbreaks, in which cases small trees are often employed (either exclusively or mixed with shrubs). The hedge plants in privacy screens or windbreaks are commonly allowed to grow naturally, rather than trimmed to a particular size and shape, unless the grower wishes to combine decorative and practical functions.
Not all hedge shrubs should be meticulously trimmed so as to form sculpted, even surfaces with straight lines. Only three of the shrubs discussed below are typically trimmed in this fashion (forming the "classic" hedge, if you will):
Examples of Evergreen Hedge Shrubs
Japanese holly (Ilex crenata) looks more like a boxwood shrub than holly shrub, bearing small, oval leaves. Many cultivars of this broadleaf evergreen are available; for hedge plants, most people select those that reach 3'-4' in height, with a similar spread. Japanese holly is hardy to zone 6. But English holly (Ilex
aquifolium), with its prickly leaves, makes a better hedge plant if you wish to combine security with aesthetic considerations. Some hollies grow tall enough to serve as privacy screens.
Boxwoods (Buxus) are the classic hedge plants. These broadleaf evergreens were adored by aristocratic Europeans for centuries as defining elements in formal garden design.
Other broadleaf evergreens suitable as hedge plants include the mountain laurels. (Kalmia) A bonus with mountain laurels is that they bloom in late spring-early summer. Don't try to trim laurels as you would boxwoods.
Among needle-bearing evergreens, yew bushes (Taxus) are perhaps the classic hedge plants. They are popular, partly because they tolerate shade. Some yews grow tall enough to serve as privacy screens. However, yews are slow growers.
Examples of Deciduous Hedge Shrubs
Deciduous hedge shrubs look great while they're in bloom, but just so-so during the winter. Also, because they drop their leaves and stand naked for part of the year, deciduous shrubs make for less than ideal privacy screens. Three of the deciduous shrubs most commonly found in hedges are rose of sharon (Hibiscus), forsythia bushes (Forsythia) and lilac bushes (Syringa). But you probably won't want to prune any of these as meticulously as you would, say, boxwood. Most people agree that forsythia, in particular, looks best when it is allowed to "have a bad hair day." To form a hedge with such a shrub, simply plant several of them in a line. Do not fuss with making them conform to precise, pre-determined dimensions.
Examples of Other Hedge Shrubs
Like mountain laurels, azaleas and privets (Lonicera) are
broadleaf shrubs that put out flowers (the former much more impressively).
However, not all varieties of azaleas and privets are evergreen; and those that
are will not necessarily grow well in your zone. Check with your local garden
center, nursery or county extension to see if you can grow evergreen azaleas or
privets in your area. If not, you can treat azaleas and privets as you would the
other hedge shrubs in the prior category (deciduous).