Many grasses, on the other hand, are native to dry, prairie settings. They have adapted to low water availability by developing dense, aggressive root systems and the ability to go dormant in periods of drought. The absence of an overstory allows grasses to capture plenty of light to fuel their aggressive growth. Competition Problems Trees and turfgrass are commonly grown together in man-made landscapes because of our desire to have both lush, green lawns and the shelter of large shade trees. This unnatural association is plagued with competition problems made worse by the limitations of urban soil conditions.
Roots compete for limited nutrients and water .
Turfgrass roots create problems for trees because of their ability to aggressively colonize the top 2-3 inches of soil. Soil air composition at greater depths is often too poor to support root function. Trees generally lose out in competition for limited nutrients and water in this region when turfgrass is present. Turf competition for water and nutrients can affect any age and size of tree, but is especially detrimental to young trees lacking well-established root systems. Trees with poorly developed root systems suffer from stunted growth.