The most common reason trees and shrubs fail to perform as anticipated is that their cultural requirements differ from the site characteristics. People often plant things they know and love from a distant state, purchase because they are on sale, or find attractive but don't understand the environmental requirements. In some cases, a site can be easily modified to make it more suitable for a desired species. Most of the time, it is difficult or impossible to change the site characteristics enough for the plant to thrive. Appropriate watering is essential for establishment of recently transplanted trees and shrubs. This becomes even more important (and challenging) for plants poorly matched to their sites. Selecting plant species that will thrive under particular site conditions is an easier and less expensive option. The first step in doing this is to understand the site where you plan to plant.