Landscapes Benefit From Mulch
North Carolina gardeners use many organic materials as a mulch. There are many good reasons to use mulch in the garden however, there is no perfect mulch that fits every application.
Mulches help prevent weed seed germination and establishment by excluding light. They are the first defense against annual weeds. One study found that the time spent weeding was reduced by almost two-thirds with the use of mulch. Mulches help control erosion and regulate soil temperatures. They keep soil temperature cooler in summer and warmer in winter. Mulch is good insulation especially valuable during rapid temperature changes. Mulches reduce water loss in the soil. Organic mulches can help improve the soil once they are broken down. Good mulches will not wash away from the site and are relatively weed free.
Get the most value out of mulch by using the chosen material properly. The depth is important. Use neither too thick a layer nor too thin a layer of it. Most weeds need light to germinate. If mulch is applied too thin or unevenly, weeds may find their way to the light. A 3-inch layer of an organic mulch is usually about the right amount to use around plants. Also, keep the mulch out at least an inch or two away from the base of a perennial and about 6 to 12 inches away from the trunk of a tree. Mulch that comes into direct contact with the base or trunk of a plant invites problems including rot and pests.
The best mulches are aesthetically pleasing and cover much of the root zone. Consider the existing trees when choosing a mulch. Under pine trees plan to use pine straw to blend with the fresh needles.
Unwanted critters are not easily kept out of mulch. Birds, snakes, squirrels, mice, and others are all searching for food, water, and shelter. Consider these ideas to limit the unwanted ones: Keep your turf and landscape plants cut to increase the exposure to predators. Pay attention to moisture levels and avoid unneeded irrigation that can attract slugs or frogs that encourage lizards and snakes. Keep bird feeders a distance from the house to discourage rodents and squirrels from becoming the meal of another creature like a fox or snake. Avoid feeding pets outside which can encourage insects and other unwanted wildlife. Store firewood away from the house to discourage insects and other small creatures.
We know that termites are often found in wood and some are concerned about using bark or wood chips as mulch. Termites are not drawn to the wood itself but to the cool, moist environment it provides. Termites can be found in similar numbers beneath bark, wood, gravel and rubber mulch. Keep the mulch depth below 3 inches to keep the moisture level low and help avoid termites. For more information check the article on Termites and Mulch.
Now is the time to prepare your garden beds with mulch for the winter. Understanding the attributes of different mulch materials can assist in choosing the best mulch for a particular location. More information is available in the publication Mulching Trees and Shrubs from NC State University.