Landscaping for Wildfire Defense – Firescaping

There is more wildfire in our future; and for many areas, it is not a matter of “if” wildfire is going to occur, but “when”. Unfortunately, many residents and their homes are not prepared to survive wildfire. There are proven steps that homeowners can take before a fire to improve the odds of human life and home survival during wildfire. One of these steps is designing and maintaining a landscape, a firescape that will reduce fire risks.

While no single aspect of firescaping, such as using fire resistant plants, can be guaranteed to save a home during a wildfire, good planning pre-fire and regular landscape maintenance throughout the year can go a long way in providing firefighters a safe place to defend your home in the case of wildfire.

A firescape doesn’t necessarily look much different from a traditional landscape, yet there are some important design rules to incorporate:

  1. Create a noncombustible area at least 5 feet wide around the base of your home. This area needs to have a very low potential for ignition from flying embers. Use irrigated herbaceous plants (lawn, non-woody ground cover and flowers), rock mulches or hard surfaces (concrete, brick and pavers) in this area. Keep it free of woodpiles, wood mulches, dead plants, dried leaves and needles, flammable shrubs (sagebrush and juniper) and debris.
  2. Keep an area of at least 30 feet from the home “Lean, Clean and Green.” Lean indicates that only a small amount of flammable vegetation, if any, is present within 30 feet of the house. Clean means there is no accumulation of dead vegetation of flammable debris within the area. Green denotes that plants located within this area are kept healthy, green and irrigated during fire season. For most homeowners the “Lean, Clean and Green” area is the residential landscape. This area is usually irrigated, contains ornamental plants and is routinely maintained.
  3. In a firescape, there are important spacing rules for plants. On a flat terrain, shrubs should be separated from one another by at least twice the height of the shrub. Distance between evergreen tree canopies should be at least 10 feet. These distances increase with increasing slope. With flammable shrubs and trees such as junipers, pines and spruce, lower tree branches should be removed to a height of at least 10 feet. Be aware that bark and other organic mulches can be easily ignited and use them sparingly.

For more detailed information on how to protect your home from wildfire, go to www.livingwithfire.info.

Less Ignitable Plants

Unlike roofs and other building materials, plants are not rated according to their fire resistance based on standardized laboratory tests. Despite this, there are many “fire-retardant” and “firewise” plant lists available to the homeowner. These lists are often simply based on anecdotal information and may not be accurate. However, there are a number of plant characteristics that homeowners living in high fire hazard areas should look for when selecting plants for their landscapes.

  1. High Moisture Content: Choose plants that stay moist and green during fire season. If ignited, they burn more slowly and with less heat. Herbaceous (non-woody) plants such as lawn and flowers possess the highest moisture content. Deciduous plants (that lose their leaves) have a higher moisture content than evergreens such as pine, juniper or arborvitae.
  2. Low-growing Habit: Plants that are low growing typically produce shorter flames and have less fuel than taller plants. Select shrubs that grow less than two feet in height at maturity or that can be kept pruned at that height.
  3. Lack Flammable Chemicals: Many evergreen woody plants, such as juniper, arborvitae, spruce or pine, contain flammable chemicals. Some of these chemicals turn into combustible gases as plants heat up with an approaching fire. These gases can burn very intensely and easily ignite other fuels around them, including the home.