Mowing Most lawn grasses naturally grow and mature at a height higher than most of us find acceptable. When part of the leaf is removed by mowing, the plants first priority becomes the reestablishment of its former leaf surface.
Leaves take priority over roots, rhizomes, and food storage.
Root growth is temporarily stopped after mowing. There is a direct relationship between cutting height and the total volume of root growth. The shorter the mowing height the shallower the root system. Grass foliage helps keep the soil surface cool by shading the root system and soil. Mowing a cool-season lawn too low will slow its growth and increase heat and drought stress.