Fire-Smart landscaping uses carefully chosen and well maintained plants that are strategically planted to resist the spread of fire to your home. To create a Fire-Smart landscape, maintenance and design are often more important than the plant species itself. That said, some "fire-hazardous" plants burn readily, and should be avoided in residential landscaping.
Fire-Smart planting is the cornerstone of a home's Defensible Space. Remember that all plants will burn if poorly maintained. Choose preferred species, maintain plant and soil health, irrigate appropriate to the species and location, and remove all dead material regularly.
Unfortunately, there are no “fireproof ” plants. Any plant will burn if exposed to enough heat for a long enough period of time. There are, however, considerable differences among plants in regard to being a fire hazard. Some plants are harder to ignite, generate less heat when burning, and produce shorter flames than other plants. These differences can be attributed to both inherent characteristics, such as naturally occurring differences among plant species, and cultural practices, such as pruning and irrigation.
Be cautious of the claims of plants with a “firesafe” label. Bethke et. al (2016) reviewed 20 years of plant testing studies and determined that across the board there is “no consistent standardized plant flammability testing or criteria for rating”. There are problems with definitions, types of testing, confusion between common and species names, consistency of plant care, and lack of testing across regions and climate areas. As a result, it is better to focus on characteristics of the desired plant and the location where the plant will be placed over a theoretical fire-resistant rating.
Fire-Smart planting requires careful plant selection, placement, spacing, and maintenance to help resist ignition and the spread of fire to your home. Fire-Smart plants are usually easier to maintain, don't contain volatile oils, accumulate less dead woody material, and are more naturally resistant to igniting from flames and embers. These plants are NOT “fireproof” and all require irrigation and frequent maintenance to resist ignition.
FIRE-SMART PLANT CHARACTERISTICS
The good news is, you don’t need a lot of money to make your landscape more fire-resilient. Fire-Smart landscaping can increase property value and conserve water while beautifying your home.
Some plants are particularly susceptible to fire: they may ignite readily and burn intensely, and should be removed or aggressively maintained if present near a home, road, or driveway. You may be required to remove some or all of these species depending on local fire codes if present within 100’ of structures.
It is best to identify fire-hazardous plants by their characteristics, structure, and maintenance. This is not an exhaustive list, and some plants not listed here may present a fire hazard when drought stressed or poorly maintained. Any plant in poor health, lacking irrigation, or with a buildup of dry or dead material may burn. Most common fire-hazardous plants typically share certain characteristics:
The condition of the plant is often as important as its species. Many fire-hazardous plants can be relatively ignition-resistant if properly maintained and irrigated, especially natives. Depending on its growth form and access to water, the same species may be ignition resistant in one environment and flammable in another. Water-stressed plants in poor condition are more likely to burn readily. Those species already identified as fire-hazardous may become explosively flammable when poorly maintained. South-facing slopes, windy areas, sites with poor soils and urban landscapes are more stressful for plants and often lead to greater hazard from burning vegetation.
Many plants are particularly susceptible to fire. Some plants ignite readily and burn intensely, and should be removed if present in a home's Defensible Space zones or close to roads and driveways.
Bamboo are fast growing grass species that can make a good privacy screen - as long as you live in outside the Wildland Urban Interface (WUI). Although some species of bamboo can be maintained in a relatively fire resistant state, their rapid moisture loss during periods of hot, dry weather and tendency to accumulate fine, dead leaf litter makes them unsuitable as a screening plant near homes. If you live in or near the WUI, choose fire-resistant screens and hedges instead.
These evergreen conifers are valued for their screening properties and low maintenance. Like juniper, they may be explosively flammable, and don't belong in the landscaping around homes in Marin's Wildland Urban Interface.
Italian cypress are often planted as an architectural compliment to mediterranean-style homes. These tall, highly combustible trees are sometimes referred to as "Roman candles" by firefighters. With a structure that is difficult to maintain free of dead woodly material and dry needles, they ignite easily. They should be removed or avoided in or near the Wildland Urban Interface (WUI). Watch Italian cypress burning on FIRESafe MARIN's YouTube channel...
FIRESafe MARIN first published a list of common "fire prone" plants in 1998. This list, created with the help of the University of California Cooperative Extension (UCCE), was later adopted by the County of Marin and all Marin Cities and Towns for their Fire Standards, expressly prohibiting the planting of these species for new home and remodel construction, and limiting thier use in existing landscaping. This list has evolved over the years, to encourage the use of properly maintained native plants, limit the spread of invasives, and better inform homeowners. Fire inspectors may require removal of existing plants on this list, or any plant that presents a hazard, if they threaten your home or neighbors. It has been revised extensively based on 30 years of observations and experience, and is now maintained by FIRESafe MARIN as a "fire-hazardous" plant list (with slightly differtent meaning). The UCCE no longer teaches from lists, preferring to instead teach the characteristincs of plants that contribute to wildfires - but FIRESafe MARIN continues to see a value in providing homeowners examples of commong fire-hazardous plants.