Grass clumps are a common sight in many outdoor areas. They are made up of individual grass plants that have grown together in a clump. The most common type of grass clump is made up of sod, which is a type of grass with a thick mat of intertwined roots. Tufts are another type of grass clump, which are made up of individual grass plants that have grown together in a dense cluster. Tussocks are the largest type of grass clump, which are made up of several tufts of grass that have grown together in a large mound.