Mulches for the Alabama Landscape

Nature mulches plants with fallen leaves and other organic materials. Mulching, as practiced by gardeners, is merely an adaptation of this natural process.

Advantages of Mulching

Mulching offers several advantages; the greatest is conservation of soil moisture. Evaporation of water is greatly reduced when soil is protected from the direct rays of the sun and moving air. Also, rain falling on mulch doesn't pack the soil surface. At the same time, erosion is eliminated.

A second important advantage of mulch is the control of weeds. Mulch greatly reduces the need for weeding. If mulch is used with a weed killer that kills weeds before germination, the benefit will be even greater. It is important to mulch rather than cultivate shallow-rooted plants such as rhododendrons, azaleas and camellias.

Controlling soil temperature is another plus for mulching. Lower and more uniform soil temperatures in summer favor beneficial bacterial activity in the soil. High summer temperatures improves beneficial bacterial activity in the soil. High summer temperatures may injure these microorganisms as well as the roots near the surface of the soil. In winter, frost penetration is less likely to occur in a mulched area. Evergreens must absorb moisture in the winter as well as summer. Therefore, a winter mulching may prevent soil water from freezing and becoming unavailable to plants.

Organic matter used as mulch can improve soil structure and tilth. As it decays the mulch material works down into the topsoil. Decaying mulch also adds nutrients to the soil.

Mulching material, such as pine bark or pine needles, improves the appearance of the garden. It is valuable for covering beds near the house or in areas where the neatness is important.

Disadvantages of Mulching

There are a few disadvantages to mulching. First, the cost of some materials can be expensive for large-scale mulching. Also, some mulches are not readily available.

When using sawdust and straw as mulch, nitrogen starvation sometimes occurs, but this is easily corrected by using additional nitrogen.

Heavy mulching over a period of years may result in a buildup of soil over the crown area of plants. This condition is especially harmful to camellias. After three years, it is advisable to remove the old mulch before applying a new layer to prevent plant roots from developing in the mulch material.