Firewise: Fire Resistant Plants

The devastating Camp Fire of 2018, along with the numerous fires North State residents have experienced since then, have led many of us to focus on creating a defensible fire-resistant landscape around our homes.   As noted in this column last Friday, the key to establishing defensible space is to utilize plants that are fire resistant and judiciously space them both horizontally and vertically.

The good news that some plants are more fire-resistant than others, but it must be emphasized that fire-resistant plants are not fireproof!  It is important to realize that creating a “firewise” landscape entails much more than choosing the right plants.  Still, a working knowledge of fire-resistant plants is a good starting point for creating a firewise landscape.  Fire resistant plants are relatively slow to ignite and tend to have certain characteristics in common.  They have moist, supple leaves and their watery sap usually lacks a strong odor.  Fire resistant plants also tend not to accumulate dry, dead material within or beneath the plant.  Plants that are slow growing will accumulate fuel at a slower pace, so they require less maintenance.   Native species can play a role in firewise landscaping as well.  Drought tolerant native plants often maintain a high internal water content without needing much water and native trees commonly have a high tolerance for fire.  Native trees may also restrict the growth of more volatile invasive species.

Examples of fire-resistant ground covers include ajuga, creeping thyme, creeping phlox, wild strawberry, snow-in-summer, sedums, hen & chicks and California fuchsia.  Some fire-resistant flowering plants are yarrow, allium, columbine, coreopsis, delphinium, gaillardia, daylily, iris, lavender, Echinacea, lupine, poppies, penstemon, salvias (which are exceptions to the aromatic sap guideline), lamb's ear, evening primrose, hosta, coral bells, dusty miller, and bulbs of all kinds.

Shrubs that are fire resistant include ceanothus, butterfly bush, spirea, rose of Sharon, Oregon grape, lilac, mock orange, potentilla, forsythia, cotoneaster, island bush poppy, currants, camellia, azalea, monkey flower and viburnum.  Aloe and other succulents are generally considered fire-resistant but avoid succulents such as ice plant that produce mats of flammable dry material.

Choose deciduous trees such as maples, oaks, sweet gum (liquidambar), locust, redbud, dogwood, ash, toyon, and smoke tree.  Citrus and deciduous fruit trees such as cherry, peach and plum are fire resistant.  Although most conifers are highly flammable, redwoods are the exception to the rule and are a desirable tree in a firewise landscape.

Highly flammable plants often have an excess of fine dry or dead material and contain volatile waxes, terpenes, or oils.  Their sap is gummy or resinous and aromatic.  They may have loose, papery bark as well.  Examples of flammable plants are sagebrush, conifers (cedar, pine, juniper, fir, Italian cypress), broom, rosemary, eucalyptus, palms, feather and fountain grasses and dry annual grasses.  These plants should be avoided when planning a firewise landscape; if they already exist in a landscape, consideration should be given to removing them. 

For more information on creating fire resistant landscapes, see the Firewise section of our website devoted to this topic.

UC Master Gardeners of Butte County are part of the University of California Cooperative Extension (UCCE) system. To learn more about us and our upcoming events, and for help with gardening in our area, visit our website. If you have a gardening question or problem, email the Hotline at mgbutte@ucanr.edu or leave a phone message on our Hotline at (530) 538-7201. To speak to a Master Gardener about a gardening issue, or to drop by the MG office during Hotline hours, see the most current information on our Ask Us section of our website.