There is good mulch and bad mulch.
Good landscape mulch is made up primarily of composted bark. When this type of mulch is prepared for use in landscaping through the composting process age and heat stabilize the product, which already is partially decayed when it is spread.
While I don’t often recommend homeowners purchase any product that is “partially decayed,” for landscaping mulch it is essential to healthy trees and shrubs. A layer of good mulch over the roots of newly transplanted trees and shrubs keeps the soil from compacting so tender roots get a faster start. It can also help moderate soil temperatures in the face of freezing and thawing cycles, preventing frost-heaving on fall-planted shrubs.
Colored mulch is not good mulch.
Colored mulch is not in that category of good partially decayed mulch that is healthy for your landscaping. You might be surprised that it has nothing to do with the hue.
Colored mulches are made from shredded, recycled waste wood, primarily shipping pallets and shipping crates. Colored mulches are fabricated from the heartwood and sapwood of logs, and they contain no bark. What’s more, asbestos and lead-based paints could be present in the recycled waste wood and can be found in the mulch if construction materials from older buildings being demolished were recycled to produce the mulch.
Good composted bark mulch cannot be dyed.
Just like when you dye clothing or your hair, the dye colors best when it can be absorbed. The dyes used in coloring mulch will only penetrate that freshly-shredded recycled wood. So, coating composted bark with the decorative pigment is not an option. Basically, it doesn’t take the color.
Gardeners know what freshly-ground wood chips do to their plants–just as they absorb the dyes, they also steal nitrogen from the soil, depriving the roots of your planted trees and shrubs of this most important nutrient. Plants can literally starve to death.
The process through which this occurs is fairly complex and involved the relative amounts of carbon and nitrogen present in each product.
Dyed wood is mostly carbon. As a host of micro-organisms in the soil goes to work digesting it, they suck almost all available nitrogen from the top 2 to 3 inches of soil. There’s where the majority of new feeder roots grow.
Bob Beisbier, owner of BK Home Inspections, is a Certified Master Home Inspector who has been providing professional and thorough home inspections in southeast Wisconsin for over 12 years. Bob is Infrared certified, DILHR Certified, and provides Home Energy Tune-ups, Environmental Data Reports, Pre-sale Home Inspections and Pre-offer Home Inspections.