Is that green bush in your yard a shrub or a hedge? Some people use the terms interchangeably, and if you don't know what the terms mean, it can be difficult to tell the difference. There are similarities between the two, but they are not the same thing and require different care.
Shrubs are woody plants with more than one stem and a mature height of less than 15 feet. Shrubs can be deciduous or evergreen and range in size from creeping along the ground to 15 feet tall. Shrubs can be left to grow naturally or they can be pruned and shaped. At times, they are pruned into a severe, formal shape or a topiary.
According to the Oxford Dictionaries website, a hedge is "a fence or boundary formed by closely growing bushes or shrubs." A tall hedge can also be made up of trees. Hedges consist of more than one shrub and have different uses. Hedges provide privacy screens, fences, visual boundaries, windbreaks and different shapes to add interest to landscaping. They are usually well-maintained with different spacing and pruning than shrubs.
When planting shrubs as hedges, spacing is important to achieve the look you want. Spacing of 6 to 8 inches for smaller, shorter hedges and 18 to 30 inches for larger hedges is ideal. On the other hand, shrubs planted on their own require different spacing. When planting shrubs, use the expected mature size of the shrub as a guide to leave space around the mature shrub and its roots.
Trimming hedges is important to maintain the proper shape. Ideally, hedges are uniformly dense from the top to the ground. Prune so the top is slightly narrower than the bottom to allow the bottom branches to fill in properly. If shrubs are trimmed so the top is wider than the bottom, top branches will shade out bottom branches and leave open space in the hedge. Also, maintaining the formal shape of some hedges requires more frequent trimming. Depending on the formality and type of shrub used in the hedge, trim twice per growing season or more. Seriously overgrown hedges may need to be cut back severely or replanted. Hedge shears or hedge trimmers are good tools to use on hedges.
Shrubs should be trimmed in their natural shape, unless they are being used as a topiary. They don't need to be trimmed often, usually only once per year. Pruning procedures vary depending on the type of shrub, the degree of maturity and the desired appearance. There are different tools available for pruning, but hedge shears and hedge trimmers are not for use on shrubs when a natural look is desired.