Why Not to Use Dyed Mulch

July 10, 2019

Consumers Beware "Don't Bark up the Wrong Tree"

There are numerous reasons why you should not use dyed mulches in the landscape. Aside from looking artificial here are a few more.

Origin of Dyed Mulch

Dyed mulches (black, red, green and other colors) are usually (with few exceptions) made up of recycled wood waste. This trash wood can come from old hardwood pallets, old decking, demolished buildings or worse yet pressure treated CCA lumber. CCA stands for Chromium, Copper and Arsenic; chemicals used to preserve wood. This ground up trash wood is then sprayed with a tint to cover up inconsistencies in the wood and give it a uniform color.

Effect of Dyed Mulch

This dyed wood mulch does not break down to enrich the soil as good mulch should. Instead it leaches the dye along with the possible contaminants (chromium, copper, arsenic and others) into the soil harming or even killing beneficial soil bacteria, insects, earthworms and sometimes the plants themselves. These wood mulches actually rob the soil of nitrogen by out-competing the plants for the nitrogen they need for their own growth. Dr. Harry Hoitink, Professor Emeritus at Ohio State University, warns that dyed mulches are especially deadly when used around young plants and in newer landscapes.

Pay Attention

It is recommended that your mulch selection comes from a reputable, local or regional supplier. There is no local control over mulch that is supplied to retail stores, especially big box locations, so quality may be misleading. Therefore, always inquire about origination before committing to a purchase.