Is Dyed Bark Mulch Toxic?

Colored MulchNew Hampshire is in the heart of hardwood country. Because of this, bark mulch is a very popular and readily available material to use around your trees and shrubs. It does an excellent job preventing weeds and holding moisture in the soil around landscape plants.

At Groundhog Landscaping, we sell a lot of bark mulch. Every once in a while, customers will ask us, “is dyed bark mulch toxic?” This is a reasonable question, especially with rising concerns for the environment.

History. 30 years ago, the bark mulch sold for use in the landscape came strictly from tree bark – mostly pine and Hemlock. However, as paper recycling decreased the demand for logging, and the popularity of bark mulch increased, the bark mulch industry began supplementing the pure bark with a mixture of dyed wood pulp. This new mulch quickly became a must-have item because of its bright, long-lasting color. Most of the landscape mulch sold today is a dyed wood product containing approximately 50% bark and 50% wood pulp.

Toxic mulch? Not long after it became popular, controversy sprung up over the possibility of dyed bark mulch being toxic. This, however, was not related to the colorants used in dyed wood mulch – it had to do with the wood itself. In parts of the country that don’t have such readily available timber, mulch recycling companies were grinding up construction debris that contain arsenic and other hazardous materials. This was years ago. Since then, the EPA ban on chromium-copper arsenate treated wood (CCA’s) and a tightly regulated construction and demolition (C&D) industry have practically eliminated the possibility of your bark mulch being toxic.

The dyes used to color bark mulch are organically based and not harmful at all. Red coloring in mulch is iron oxide (also known as “rust”) and black mulches are derived from carbon (also known as “charcoal”.) These same colorants are used in cosmetics and floral arrangements. In fact, iron oxide provides iron to the soil – a necessary micro nutrient for landscape trees and shrubs.

Is colored bark mulch safe for dogs? The bark mulch that we use at Groundhog Landscaping is locally produced and non-toxic to the environment and to pets. However – as far as your four-legged friend is concerned – you may want to consider ¾” river stone or 3/8” pea stone as a bedding material for dog kennels and resting areas. It’s easier on their paws, cooler in the summer, and less likely to get picked up in their coats. We have all of these landscape materials available for delivery at Groundhog Landscaping’s Derry NH location.

Yes, we are big fans of colored mulch here at Groundhog. It’s clean, safe and long lasting. It protects plants root systems from heat stress. It controls weeds. When we buy it, we support the northern New England economy. And – best of all – colored bark mulch makes our client’s yards beautiful!

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