Drainage problems can be related to the grade or slope of the site. Both dry and wet situations can occur. Plants on the top of a berm or slope may suffer from dryness. Water will soak into the soil at increasingly slower rates as the surface layer becomes saturated. If water is applied faster than the soil will absorb it, the excess runs off the hill and does not benefit the plant.
Wet spots occur in low areas where water collects from surrounding higher ground.
A similar situation occurs when a tree or shrub has a planting well around it. If the surrounding lawn is watered too often, the water may run into the planting well and drown the plant. Wet areas can occur where downspouts from the eavestrough empty. Often this is near the base of a plant, which is injured by the excessive amounts of water. Plants growing in mulched beds or planted in slight depressions will be most seriously affected.