The trick is to give your plants enough water without giving them too much water. Why? Watering too little can lead to wilt from which the plant may not recover, but watering too much is bad for plants because it starves the roots of oxygen. Depending on the size and type of the plant (tree, shrub, or groundcover), you will need to water to different depths and widths. A large tree needs more water than a small groundcover because it has a larger root zone— the area in which the plant’s feeder roots are concentrated. Your plants will be healthiest if you completely wet the root zone each time you water.