Fire Resistant Premium Woodchip Mulch is used around buildings where the potential for fire may be increased due to disposed cigarettes or other forms of flame.

  • Ground, clean, virgin wood
  • Very slow to decompose 
  • Same great properties as EnhanceĀ® Premium Woodchip Mulch 
  • Colourant contains a natural iron oxide formulation 
  • Fire retardant is a horticultural grade of ammonium sulphate fertilizer 
  • Available in dark brown
Reducing the Potential for Fire in Mulch: 
Keep Gardens Irrigated

In a Gro-Bark conducted study; untreated woodchip mulch that was kept at a moisture content of greater than 12% did not ignite. Installing an irrigation system around buildings may be beneficial. The cost to install an irrigation system is approximately $0.13 per square foot or $800 for 6000 square feet. Yearly maintenance and water costs are approximately $200-$300 per 6000 square feet depending on region. 

Mulch Selection 

In areas that are at higher risk of fire, consider using products with greater resistance to ignition and spread. 

  • Use woodchip mulch as opposed to shredded mulch (Hickman). 
  • Use composted as opposed to fresh mulch (Smith and Quarles). 
  • Avoid highly flammable mulch types such as decorative rubber and pine straw (Steward).
Use a Fire Retardant Spray 

Weatherproof exterior pyrolitic fire retardant penetrants are used to coat wood surfaces. When applied correctly, this type of chemical can self-extinguish fire with minimal smoke. Product is applied to the surface, which means the underside of the mulch is untreated. The cost of using this type spray-on treatment starts at approximately $0.80 per square foot or $100 per 125 square feet for a double coat with 2-3 years durability on an undisturbed surface.

Product Longevity 

Please Note: Gro-BarkĀ® has used a liquid fire retardant that is not permanent. The fire resistance of this woodchip mulch will decrease over time due to temperature, moisture, and wear. It is important to top the mulch up regularly in order to maintain a fire resistant area, and to follow suggested risk reduction guidelines.

Download a copy of this bulletin

1. Hickman, G.W., and Perry, E. 1996. Using Ammonium Sulfate Fertilizer as an Organic Mulch Fire Retardant. Journal of Arboriculture. 22(6): 279-280.
2. Smith, E., and Quarles, S. 2011. The Combustibility of Landscape Mulches. University of Nevada Cooperative Extension. Leaflet SP-11-04.
3. Steward, L.G., et al. 2003. The Ease of Ignition of 13 Landscape Mulches. Journal of Arboriculture. 29(6): 317-321.