Mulches are a garden's finishing touch. Not only do mulches cut down on weeds and erosion, they add texture and become a unifying element throughout the landscape. However, not all mulches are created equal; rubber mulches have widely different physical properties than wood mulches. Understand the benefits of both and make the right choice for your garden.
Most rubber mulches are fade-resistant and decompose slowly. A Consumer Reports test showed that one brand of rubber mulch retained its color after 32 weeks of weather exposure, while a second rubber mulch brand and a wood mulch sample faded. Despite the fading, rubber mulches last multiple seasons after the initial placement, while wood mulches eventually decompose.
Wind, rain and watering shift wood mulches. The heavier rubber mulches interlock and are not easily disturbed. These shredded mulches stay in place and give a yard a tidy appearance. Additionally, rubber mulches are available in many colors to complement house colors, while manufacturers leave wood mulches untreated or occasionally dye the wood red. Both wood and rubber mulches are equally as effective in suppressing weeds, according to the Alabama Cooperative Extension.
Rubber mulches, according to the 2009 Consumer Reports article, cost between $13.75 and $15 per cubic foot. In contrast, basic wood mulches cost $1.50 per cubic foot. Rubber mulches do not need annual refreshing as wood mulches do. After roughly nine years, the one-time cost of rubber mulch is equivalent to the annual cost of wood mulch, assuming 2009 pricing.
Wood mulches eventually improve the soil as they decompose. They often contain recycled wood or arborist's cuttings. Rubber mulches recycle used tires, but they may leach toxic substances such as arsenic or lead. Rubber mulches may also expose homeowners to allergens like latex.
A 2008 Environmental Protection Agency memorandum outlines concerns regarding recycled tire products, including human exposure to "respirable particulates and fibers," "inhalation of volatile organic compounds" and "ingestion of heavy metals and dyes." Rubber mulches may also contain wire remnants of shredded tires. Wood chips often have sharp splinters. Both wood and rubber mulches are flammable, but Consumer Reports warns that rubber mulch fires are more difficult to extinguish.