Marin IJ Articles

Native plants in a fire-smart landscape

• Barbara Robertson

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  Among the 32 varieties of stonecrop native to California is Sedum spathulifolium. The perennial succulent grows to 6" tall by 2' wide. B. Robertson

  Sparked by the increasing number and intensity of wildfires, the California legislature has passed laws regarding fuel modification in areas surrounding structures. One looks at the 100-foot area surrounding a structure (or to a property line). Another passed in 2020 (AB3074) considers an “ember resistant” zone from zero to five feet of a structure. These laws have become codified as California Public Resources Code (PRC) 4291 and are scheduled to become effective January 1, 2023 for new construction; the following year for existing structures. PRC 4291 defines “fuel” as any combustible material including petroleum-based products, cultivated landscape plants, grasses, weeds, and wildland vegetation.

  Of particular interest to gardeners is a requirement in the code that the board and State Fire Marshall develop a guidance document that “shall include, but not be limited to, regionally appropriate vegetation management suggestions that preserve and restore native species that are fire resistant or drought tolerant, or both, minimize erosion, minimize water consumption, and permit trees near homes for shade aesthetics, and habitat….”

  

  This beautiful fire-smart garden in Novato has hardscape and appropriately spaced native plants growing up the hillside. Photo: Barbara Robertson

  We spoke with UC Master Gardener Bob Mauceli who frequently gives public seminars on fire-smart landscaping, and to Steven Swain, Marin Environmental Horticulture Advisor about the reason for using native plants in a fire-smart garden.

   “We don’t rely on plant species for fire resistance,” Swain says. “Instead, we rely on maintenance and landscape design; on watering and pruning. We choose natives because they have the least environmental impact. If you’re living near a wildland urban interface, why not support the wildland?”

  When you think about which native plants to place where, the Master Gardeners’ basic suggestions for fire-smart garden design with any plants apply: Create horizontal and vertical spacing to minimize flames spreading from one plant to another. Know that flames can rise three times the height of a plant. Separate plantings with hardscape. Remove dead and dry branches and plant debris. And close to the house, eliminate things that embers might land on and easily catch fire.

  PRC 4291 guidelines for the ember-resistant, zero to five-foot area aren’t released yet, but well-kept, low-growing, herbaceous (non-woody) plants separated by pebbles or rocks, and low-growing potted plants in non-combustible pots might be allowed depending on where you live and your type of house. In terms of natives, such succulents as Dudleya, Stonecrop, and Lewisia might work – plants that stay green through the summer with little water. Or, short annuals and bulbs that you can cut back before fire season. 

  Know, though, that the final guidelines for the state code will be a baseline. Counties, cities, and local fire agencies could have stricter defensible space rules – your local fire agency will be your authority. 

  

  The evergreen native Ceanothus is available in many varieties. Ceanothus Blue Jeans, can quickly grow to 3' tall by 6' feet wide. Photo: Bob Mauceli

  Farther from the house, consider size, height, and ease of maintenance. Within the five to 30-foot area, Mauceli suggests short natives such as the smaller Ribes, small Salvias, ground covers, and low-growing Ceanothus – again bearing in mind horizontal and vertical spacing, especially beneath trees. Beyond 30 feet, consider Manzanitas, the larger Ceanothus and Ribes, and other large shrubs. 

  These are but a few of the numerous California native plants that require less water than many exotic species. Plants such as these can be a valuable benefit when you want to use minimal water to have well-hydrated vegetation in your landscape during fire season, especially in drought years when water is scarce. So, in addition to supporting native wildlife, insects, butterflies, and other pollinators, native plants can be an excellent choice for a fire-smart landscape.

  

  Found throughout California, the spring blooming annual Baby Blue Eyes Nemophila menziesii stays under a foot tall & wide in many habitats. Bob Maucel

  For more information on fire-smart landscaping, visit https://marinmg.ucanr.edu/basics/firesmartlandscaping and come to the UC Marin Master Gardeners’ display at “Ember Stomp,” a free wildfire prevention festival on Saturday May 28, 2022 from 11 to 5 at the Marin Center Fairgrounds Island. In addition to valuable information on creating defensible space in your garden and home hardening ideas, there will be live music, activities for the kids, and great food.