MULCH RINGS FOR TREES IMPROVES HEALTH
Homeowners and professional arborists depend on mulches in landscapes for several reasons. Functionally, mulches discourage weeds from growing, conserve moisture during drought periods, and allow better use of water by controlling runoff and increasing water-holding capacity of light, sandy soils.
Mulches help maintain a uniform soil temperature. A 2 to 4 inch layer of mulch can add to the aesthetic value of a garden while protecting the base of trees from being injured by mechanical equipment.
Mulch rings also decrease competition from lawn grass. Lawn grass, especially when well maintained, robs trees of valuable nutrients and moisture.
Many organic materials can be used as mulch. Bark mulches and wood chips are the two most commonly used mulches in most of the country. In the south, pine needles are included in that list.
Mulch can be applied just about any time of the year when trees and shrubs are being planted. The best time to apply mulch in established bed areas would be in mid-spring when soil temperature has warmed up enough for sufficient root growth. If applied earlier, the mulch could lower soil temperature and delay root growth.
Mulches should be applied 2 to 4 inches in depth over relatively clean, weed-free soils. Never pile mulch more than 4 inches high. Identify and eradicate weeds before the mulch is applied. Do not allow mulch to touch tree trunks and keep mulch back about 6 to 12 inches. Trees can be mulched out to the drip line also.
Most arborists consider organic mulches as the most compatible with trees. There are, however, several inorganic materials used as mulches, including weed barriers. Black plastic is sometimes used to discourage weeds, though it interferes with the normal oxygen and water supply to the tree's roots. Plastic barriers can contribute to the creation of a very shallow root system, which, during drought periods, make plants less capable of obtaining water or withstanding heat stress. Therefore, it is not recommended to use black plastic around trees. There are, however, several landscape fabric mulch products available that will function in the same way as plastic but allow for normal water and oxygen exchange. These materials are placed on bare soil around trees and shrubs wit the mulches used on top. There are many brands and types of materials for which to choose that have proven to be beneficial in discouraging weeds and holding soil moisture.