As you prepare for wildfires and with the ongoing drought conditions, it is important to make fire-wise decisions to protect your home and property. This includes the use of mulch as a ground cover. Mulch can provide benefits around your home however, mulch can be combustible and residents located in or around our Wildland Urban Interface (WUI) should learn about the best possible mulch types to use and where it should be placed around your home.
Mulches fall into two main categories, organic and inorganic. Organic mulches usually consist of pine needles, wheat straw, pine bark nuggets, shredded cedar and redwood bark, and other recycled wood chips. Inorganic mulch consists of non-plant material such as rock, gravel, and brick chips, which can be categorized as hardscape. Hardscape can also consist of rocks, stones, bricks, and concrete pathways.
The main benefit of mulch is that it keeps the soil temperature cool and moist, which in the long run conserves water. Hardscape material increases the temperature making your soil, plants, and trees hotter than normal which, in turn, requires more water to keep them healthy.
Using the appropriate mulch is key and planning out locations of plants or garden beds that will need the mulch is equally important. Avoid “gorilla hair” or other shredded bark mulches around homes, decks, fences, and other combustible structures. We recommend at least 30’ of clearance from your home if they are in use. Compost or large bark chips are usually the best option for fire resistance. Fine (less than ¼”) or stringy mulches ignite, burn easier and can be difficult to extinguish when the mulch is greater than 2” in depth. These mulches contributed to fire spread and damage during the 2017 fires and the most recent Glass Fire in 2020.
We recommend not using wood or bark mulches within 3 to 5 feet of your home. Homes built in the WUI after January 1, 2021 are required to have a 3’-5’ “Ignition Free Zone” and only inorganic, non-combustible ground covers or mulch can be used. Learn more at srcity.org/WildfireReady.
Visit srcity.org/WildfireReady and go to the Resource Library where you’ll find more information on the "Combustibility of Landscape Mulches” and other helpful documents and videos on creating defensible space around the home.