Fire Resilient Landscaping
“The right plant in the right place.”
Fire resilient landscaping focuses on creating and maintaining defensible space around your home. Defensible space is the area surrounding your home and all structures attached to your home (decks, car ports, patios, garages, etc.). The landscape surrounding your home can become fuel for a wildfire, and the goal of a fire resilient landscape is to have fire-resistant plants strategically placed in your landscape to reduce the chances of wildfire reaching and burning your home.
The Right Plant
While there is no “fireproof” plant, there are plant characteristics to consider when planning a fire resilient landscape.
Fire resistant plants possess chemical and physical properties that reduce the plant’s combustibility and ignitability. These types of plants can withstand a longer exposure to heat and embers before igniting and burn less intensely. Typical traits of fire-resistant plants include a high-moisture content and stems that are watery and lack resins, oils and other volatile compounds.
Highly combustible plants will produce large amounts of heat and long flame lengths, and when planted near other vegetation, these plants can contribute to the spread of a wildfire. Plants can also scorch a home if they are planted nearby. Another consideration is ember production. Plants that produce a large amount of embers will increase a home’s risk in the event of a wildfire. Embers can land in leaf litter, pine litter or enter the home through vents and other openings.
When selecting plants for your fire resilient landscape, it is important to plan for how the plant will grow throughout its life cycle. Plants with higher growth rates will require more maintenance, especially when planted near structures or other plants. A plant’s growth habit is also important when planning your landscape. Growth habit describes the shape of the plant as it grows. When selecting a plant or planting site, ask yourself: “What will this plant look like in 5 years? In 10 years?”. In general, low-growing plants that are less dense are typically more fire resilient since they help maintain the vertical separation of fuels and produce less material to burn.
“The Right Place”
As you plan your fire resilient landscape, organize your plantings to allow for horizontal and vertical separation of plants. Treat every plant as potential fuel for a wildfire and allow enough separation between plants to prevent flames from spreading plant-to-plant. This includes both horizontally and vertically.
Forests have layers of vegetation: forest floor, shrub, understory and canopy. When left unmanaged, these layers can overlap and create a condition known as “ladder fuels”. Ladder fuels allow a fire to “climb” from the ground to the crown of a tree.
To increase our yard’s fire resilience, it is important to prevent ladder fuels from occurring. Keeping your tree’s lower branches pruned and your shrubs trimmed to allow for 6 to 10 feet of open space can help keep flames on the ground and out of the crown. Burning trees and shrubs can easily have flames reaching twice as tall as the plant, so the taller your shrubs, the more space they need above them.