Shrubs could be described as those in between plants that are larger than flowers but smaller than trees. In fact they form an essential part of the landscape by providing a backdrop to the flower border. As with most aspects of gardening there is a right way and a wrong way to use shrubs in a garden as Lynne Cherot explains in her article which I found on the Sensible Gardening website.

Of all garden plants, shrubs are probably the most well used. A shrub is basically any woody plant that is smaller then a tree and having more than one stem.
Using shrubs effectively in your garden with Sensible Gardening
There are deciduous shrubs which loose their leaves each year and evergreen shrubs having needles or broad leaves. Shrubs vary in size and growth habits and are extremely versatile in garden design.
Using shrubs in the Garden with Sensible Gardening
An extra bonus of many border shrubs is their ability to flower, ?berry and/or the coloration of their leaves. Many change to beautiful shades of orange, yellow and red during cold falls. With so much variation in size, shape and texture shrubs can be combined artfully to create outstanding landscapes. If you enjoy wildlife in your garden, shrub borders are invaluable for providing food, nesting and protection. Shrubs are also a long term investment which if properly planted require very little maintenance and replacement. This saves the gardener both time and money.
Using Shrubs in the Garden with Sensible Gardening
How to Use Shrubs:
The mixed shrub border is created using similar principals as the perennial border. Variations in height, width, flower and foliage colors and shapes all need to be taken into consideration. Do your homework as this will be a long time decision. By choosing shrubs that all flower in the same season you create an outstanding display for that season alone. Choosing shrubs with differing bloom times will extend the borders interest over several months. You might also prefer a shrub border of less color, with more emphasis on graceful shapes and textured leaves, or all evergreens.

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