The right mulch can just about eliminate the need to pull weeds. Only the most tenacious perennials poke through, such as yellow nutsedge or johnsongrass.
Mulches also prevent weeds seeds from reaching the soil.
Instead, they fall on an inhospitable surface, where they languish. By covering the soil surface, mulches reduce the amount of sunlight and wind that reaches the soil, so water evaporates from the soil more slowly. Finally, mulches can make a garden more attractive, especially a new one where the plants have yet to fill in. And when it rains, a mulch keeps soil from splashing onto the leaves or nearby paved surfaces or buildings. A Few Cautions Mulches do have some drawbacks.