SP617 Mulching Your Trees and Landscapes

A protective covering of various materials, either organic or inorganic, spread over the soil surface to reduce evaporation of moisture, improve plant growth, discourage weedy species and enhance the appearance of the landscape is known as mulch. Inorganic mulching materials include landscape fabric (geotextile) and plastic fi lm that are primarily used for weed control and retention of soil moisture, while rocks, gravel, brick chips and shredded rubber are used more for decorative purposes. Most inorganic mulches do not decay and thus do not improve soil properties. Grass clippings, straw, pine needles, leaves, peat moss, compost, wood fiber and bark are organic mulches composed of decaying plant materials. Over time, organic mulches will decompose and become part of the soil, adding to the soil’s organic matter, improving soil structure and nutrient availability and helping the soil retain moisture. However, as the organic mulches decompose, they must be replenished.