Sometimes it is easier to explain how to do something by explaining how not to do something. "The Carolina Yardstick Workbook" has a page called The Top Five Common Mistakes in Landscape Plantings. This information was adapted from "Landscape Design" by Greg Davis, Ph.D.
Mistake No. 1 is overplanting. Initial landscape plantings are often planted too close, which provides immediate gratification. In a few years, plantings of this sort grow into a crowded mess. The solution is to know the mature heights and widths of plants before they are planted. Plants must be given sufficient room to grow. In the first few years, patience is required.
There is a whole subset of landscape contracting that exists simply to straighten out overcrowded landscapes. The problem is prevalent. Many folks are spending money to redo plantings that were overcrowded in the first place.
Mistake No. 2 is cluttering lawn areas with trees and shrubs. This can lead to a very unorganized setting. The idea of planting a tree here, a bush there and a flower over there creates several problems. It creates a landscape that is "thingy" (one thing here, another thing there). Watering, mowing and other maintenance becomes haphazard and uncoordinated.
Lawn areas should be clean and neat and maintain their appropriate function (i.e. foreground for a focal point, recreation area, etc.). This leads to ease of maintenance. Conversely, trees, shrubs and flowers do best in bedded areas where they have the same watering and maintenance schedules.
Mistake No. 3 is allowing shrubs around the house to grow too tall. The plants start to block the windows and other architectural features of the house, requiring massive shearing to make the plant "fit." This is frustrating and time-consuming. It saves a lot of time and effort to have the right plant put in the right location. A minimal amount of selective pruning is required when using dwarf plants for a foundation setting.
Mistake No. 4 is placing plants too close to the house. Again, it is important to know the mature size of the plant at the time of planting. The formula here is to cut the mature width of the plant in half and add a foot. If the plant grows 5-feet wide, one-half the width is 2.5 feet. Add a foot and the distance to plant away from the house is 3.5 feet. Plants placed too close to the house overpower the setting and detract from what they should be enhancing.
Mistake No. 5 is scattering bright colors throughout the yard. Too much of a good thing leads to confusion. If the eye is overwhelmed, it doesn't know where to focus. Colorful accents should be used to enhance focal points, not to compete with them.
These landscape mistakes can be divided into two categories. The first is the problem with plant sizes and the second category is design problems. I cannot stress enough the importance of knowing mature plant sizes when planning landscapes. Plants should be enjoyed for years. When we constantly have to hack back plants to make them fit into our landscape – well, there's no enjoyment in that.