Proper Mulching
By: Janeth Duque

Mulch is any type of material placed over the top of the soil to improve the soil. Mulch helps the soil retain moisture and can improve soil conditions. Additionally, mulch reduces weed competition by restricting the number of weeds that grow around your landscape plants. You can improve the health of your plants by using mulch around them to minimize damage by lawn mower blight and weed whacking. When one practices proper mulching, it can actually help the landscape maintain a healthy appearance. It can even contribute to the look of a well-groomed landscape. It is important, however, to properly apply your mulch. If it is not applied properly, you might find that rather than helping, you can cause harm to your plants and trees.

There are many different types of mulch. Just as there are different fertilizers, mulches come made from different materials. They can be bought commercially, or you can create your own mulch and save money. The two main classifications of mulch are inorganic and organic. Many people believe that all mulch is organic, but it is not. Inorganic mulches, while more effective at keeping out weeds, will not add to the composition of the soil, as it contains no nutrients to put into the soil. Inorganic mulches include various types of pulverized rubber, some geotextile fabrics, and even stones and lava rock. Organic mulches are comprised of things like woods chips, bark, leaves, pine needles, compost mixtures, cocoa hulls, and other mulches derived from plants. Even shredded paper, used in small amounts, can contribute to organic mulch.

The first thing to realize when properly applying mulch is that there is such a thing as too much. Too much mulch can result in a variety of problems. Because mulch does help retain moisture, too much mulch can lead to excess moisture. Especially in trees, this can lead to root rot. Do not pile mulch against the stems of plants or the trunks of trees, as this can cause stress on the plant tissues and lead to pest problems. Too much mulch can also alter the pH of the soil, causing toxicities or deficiencies. Piled mulch provides nice homes for rodents, which in turn may chew the plant roots and cause tree girdling. Fine mulch can become matted if too thick and then prevent air and moisture penetration. Be aware of the type of mulch you are using. Replace inorganic mulch each year, and if you have mulch that breaks down slowly (like mulch containing cypress bark), do not add more mulch each year. Wait until the mulch is mostly broken down before adding a new layer.

Proper mulch depth is about two to four inches deep, and not directly up against trunks or plant stems. For trees, mulch should be applied at least out to the drip line, with a space between the mulch and the tree. The drip line is the border of the canopy of the tree. Root systems extend beyond the drip line, so it is okay to spread a thin layer of mulch beyond the drip line. In order to properly apply mulch, it is important to take into account several factors. You should first inspect the area. Find out if there is enough drainage, you should also determine whether the type of mulch you will use is compatible with the plants you have. Check the depth of already placed mulch and do not add more if the depth is sufficient. Rake the mulch to prevent matting. There are vegetable-based dyes that can improve the appearance of mulch that may be fading, but that does not need to be replaced. If there is poor drainage, 2 inches may be too much. Apply a thinner layer of mulch in these areas to prevent too much moisture retention.

The benefits of proper mulching are many. When properly applying mulch, you are contributing to the health of your landscape, making it more resistant to disease, insects, and drought. Organic mulches also contribute to the make up of the soil, adding nutrients and making the soil richer and better for the plants. By making good use of mulch, and avoiding excesses, it is possible for you to increase the health of your landscape and decrease the costs associated with maintenance and treatment.