Mulch is an important landscape element that does more than look good. Mulching around garden plants and hedges improves soil quality, prevents weed growth, protects roots from heat and cold, and helps retain soil moisture. If applied incorrectly, though, you can inadvertently cause more harm than good. For instance, too much mulch can prevent air and water from reaching the roots. Mulch applied close to the stems can provide the perfect place for mice to hide and chew bark. Lay mulch properly and in moderation so you can spend your attention elsewhere in the garden.
Select a mulch based on its desired purpose. To prevent erosion in windy areas, for example, a rock mulch is an appropriate choice. To improve the soil quality, choose a fine organic mulch that decomposes quickly, such as shredded leaves.
Gauge the thickness of the layer of mulch you apply to the density of the material you use. For instance, apply a 1-to 2-inch layer of a fine, dense mulch, such as pine needles or finely shredded bark, so it does not prevent airflow and water from penetrating the soil. A coarser material, such as wood chips or cocoa hulls, doesn't mat down as much and allows air in between its pieces, so you can apply a thicker, 3- to 4-inch layer of mulch of these materials. In general, 1 cubic yard of mulch covers 100 square feet of space at a depth of 3 inches.
Apply mulch around your hedges after the ground freezes if it is used to keep the roots from heaving in winter or to prevent plants from shooting up during a temporary warm spell in winter or spring. Apply mulch after planting to keep transplants and newly planted shrubs safe from fluctuating soil temperatures. These mulches should be removed after their job is done and reapplied at the same time the next year, if necessary. Alternatively, apply mulches used for appearance, to control weeds and conserve soil moisture any time and replenish them one or two times a year as needed.
Apply the mulch evenly around the edge and in between the shrubs at the desired depth. Do not apply the mulch within 6 inches of the stems. Otherwise, pests and diseases are more likely to become a problem. Extend the mulch as far out as you want to create the desired look, however, it should at least extend to the drip line of the shrubs.