Mulch serves a practical and decorative function. It can give dimension and personality to your landscape while also conserving soil moisture, reducing weed growth, and if organic, eventually decomposing to provide necessary nutrients.
When choosing a mulch for your landscape, it pays to consider the maintenance requirements. Organic mulches will decompose over time and need occasional replacing; inorganic mulches wash away with heavy rains and will eventually need you to add additional material. Mulch is a worthwhile addition to any home's landscape -- so long as you choose the right option.
Organic mulches include bark, wood chips, chopped leaves, pine needles, sawdust, and straw. If you live near a nut farm, pecan shells make good mulch too. These mulches break down and improve soil by adding nutrients.
Bark: Ground or shredded bark products are a popular mulch medium, and depending on the size of the pieces, can add textural interest. Keep in mind that as bark decomposes, it will use up some of the available nitrogen in the soil. This is true of all wood-based mulch products.
Sawdust: Sawdust provides a neat appearance, but since it is lightweight, it is not suitable for windy areas.
Pine needles: Pine needles offer textural interest and are suitable for areas where pine trees provide a ready source.
Straw: Straw is an informal mulch, and also prone to blowing around in windy areas. Save this for your vegetable garden.
Pecan shells: Pecan shells make an interesting mulch. If you have a pecan farm in your area, it makes sense to take advantage of the availability.
Pomace: Pomace is the pulpy remains of grapes or apples after pressing. They make a good mulch. Just be sure to let them dry out before adding them around your plants.
Grass clippings: These work well as a mulch, unless it comes from Bermuda grass. Never use Bermuda grass clippings or you will end up with an invasion of unwanted grass under your plants.
Organic mulches should be placed around plants about 2 to 4 inches deep. Never place too closely to the plant crown, as this will encourage rot. If you are concerned that organic mulches will attract termites, research has proven this rumor to be false. In test studies, termites appeared in areas around homes both with and without mulch, equally.
Inorganic mulches include landscape rock or gravel, sea shells, river rock, and other inert materials. The bonus of using decorative rock is it can be aesthetically pleasing. However, keep in mind that rock will do nothing to benefit the plant; you might want to consider using organic mulches at the base of the plants and inorganic mulches for dust control, informal walking paths, and non-landscaped areas between plants. Landscape rock comes in varying shades of natural colors.
Decomposed granite: As the name implies, this is granite-based landscape rock in a crumbly form. It does continue to degrade, requiring periodic replacement. It is available in a number of sizes.
Crushed rock: Unlike decomposed granite, crushed rock holds its shape and is less likely to need replacing.
Landscape glass: A fairly new introduction to the landscape world is landscape glass. Available in multiple colors, shapes, and sizes, you can add a splash of sparkling color to areas in your yard.
Inorganic mulches are usually applied to a depth of 2 to 3 inches.
What not to use
Avoid using black plastic or landscape fabrics underneath your inorganic mulches. Plastic prevents rainwater absorption and will deteriorate over time -- leaving you with a plastic nightmare to remove. Landscape fabrics eventually collect dirt on top where weed seeds can sprout, extending their roots through the fabric into the ground and creating a maintenance disaster.
Linda is a landscape architect and certified arborist in southern Arizona. With over 20 years experience in landscape design, she also has a passion for all plants and gardening. As a freelance writer for a number of websites, she has produced hundreds of articles on plants, plant care, and design.