Landscape Bark Vs. Hardwood Chips

Landscape Bark

• Landscape bark mulches are most commonly made from softwood trees such as pine, fir, redwood and spruce. Categorized by size, there are three commercial grades used for landscape use: chunks, granules and shredded bark. Bark chunks, also called nuggets or mini-nuggets, are the most decorative and the most persistent, according to Cornell University’s Department of Horticulture. Arborists, sawmills and utility companies use debarkers to remove tree bark before shredding and grading it for landscape uses.

Benefits and Disadvantages of Landscape Bark

• Bark mulches stay in place on level ground without blowing away. When used on slopes, however, they tend to wash downhill. They resist compaction and allow good water penetration to soil below. Pine bark retains its reddish-brown color without fading. Cedar bark (Thuja spp.) produces thujone, a phytochemical that repels termites, according to Linda Chalker-Scott of Washington State University Extension. Composted bark is used as a soil conditioner and as an ingredient in potting mixes.

Hardwood Chips

• Hardwood chips come from deciduous trees such as oak and maple. Arborists and utility companies run debarked wood through chippers, with the resulting chips being recycled back into the landscape as mulch. Compared to bark mulch, which can retain its color over multiple seasons, hardwood chip mulch colors fade quickly. Weathering grays their natural tan or brown shades. Chalker-Scott says wood chips are one of the best mulch choices for trees and shrubs for moisture retention, temperature moderation, weed control and sustainability.

Benefits and Disadvantages of Hardwood Chips

• Many gardeners are reluctant to use hardwood wood mulches because of their concern that mulches will attract termites. Although subterranean termites may feed on wood mulch, they live underground whether mulch is present in the landscape. In the field, termites were detected with equal frequency beneath mulches of hardwood, pea gravel and bare, uncovered soil, according to research at Iowa State University Extension. Chip mulch should not be avoided, but it should be pulled several inches away from a home's foundation. As hardwood chips decompose, they deplete soil nitrogen from plants so additional nitrogen fertilizer may be required to compensate for the temporary deficiency.