Choose fire-resistant plants that will lessen the volume of fire fuel

PHOTOS BRIAN BALLOU Many wildflowers, whether annual or perennial, are fireresistant, especially if they’re in an environment designed to be unfriendly to fire. Green grass and other healthy, watered plants compose a landscaped environment that not only presents few fuel opportunities for wildfire, it shields potentially vulnerable urban fuels, such as the wooden fence.

Bitterbrush and lodgepole pine create a nearly continuous fuel bed. Heavily thinning the bitterbrush and a light thinning of the lodgepole would dramatically reduce the risk of high-intensity wildfire in this wildland/urban interface environment. Injecting some fire-resistant plants, such as aspen, may also help.

As the gospel of defensible space  spreads among residents of wildland/urban interface areas, people are paying more attention to fire-resistant plants. Essentially, these plants can significantly reduce the volume of available fuel near homes.

Depending on which part of the country you're in, there may be hundreds of fire-resistant plants to choose from. Dogwood, aspen, rhododendron, Oregon grape, thyme and vine maple are just a few examples of fire-resistant plants. Conversely, western juniper, eucalyptus, Scot's broom, gorse, bitterbrush and manzanita are fire-vulnerable plants. In many locations, the list of fire-resistant plants is actually longer than the list of fire-vulnerable plants.

Douglas fir and ponderosa pine are also fire-resistant, but you should be aware that these trees also help create an environment that favors frequent, low-intensity fires. Ponderosa pine in particular sheds needles and bark chaff-seemingly continuously-to breed a perpetual ground-level fuel bed. Controlling needlecast and trimming low, dead branches keeps these trees from becoming a problem. In general, when incorporating these trees in a fire-resistant landscape, favor mature, healthy trees whose crowns are full and green.

A fire-resistant plant generally has supple leaves and exudes watery sap-if it weeps any sap at all. It also sheds relatively little debris that will dry out and become fine fuel, and the canopy is open so air and water can circulate at the plant's base.

Note: Fire-resistant plants are not fireproof. A fire-resistant plant will burn if it is challenged by too much heat, has prolonged contact with flame or if the plant becomes too dry. Therefore, plant arrangement and plant care are as important as plant selection. Arrange plants in small beds that are removed from the house. Landscaping beds are all too often placed adjacent to house siding, beneath roof eaves and underneath windows. A better arrangement is to move landscaping beds out from under eaves and into areas where they can capture more sun and rain. That way if fire should transfer into a landscaping bed, the fuel will be quickly exhausted, and the house won't be within easy reach of any heat and flame that's created.

Another tip: Choose plants native to the area in which they'll be planted. Localized plants have a better chance for long-term survival, and may be less vulnerable to some pests and diseases. In many cases, localized fire-resistant plants don't require much fertilizer and often don't need insecticides. In Western landscapes, where water availability is often a concern, drought-resistant plants that are also fire-resistant are good choices for sites in wildfire-prone areas.

Finally, ensure the fire-resistant plants you're considering aren't also on somebody's list for undesirable non-native species. Iceplant, for example, is fire-resistant, but it is also considered undesirable because as an introduced species, it is highly adaptable and can squeeze out native plants. County extension agents or wildlife biologists often have lists of undesirable plants that they'd prefer you not use.

There's a lot of information about fire-resistant plants on the Internet. Using your favorite search engine, type in "fire-resistant plants"; hundreds of listings will pop up. You can refine your search by adding a specific state to your search criteria.

County extension agents, urban foresters and master gardeners can also offer a great deal of information about fire-resistant plants, plant selection for specific sites and plant care. These professionals can offer advice about which plants to use in troublesome locations, such as underneath power lines or in riparian areas, and where to find locally grown plants. Also, some non-government enterprises, such as Lowe's home improvement stores and Sunset magazine, have advice for their customers about fire-resistant plants and firewise landscaping.

Homeowners who have taken the plunge and replaced fire-vulnerable plants with fire-resistant plants generally like the result. Many fire-resistant plants add color to the yard and, when coupled with a properly executed defensible-space project, actually improve the appearance of a residential landscape.

Brian Ballou frequently teaches wildland/urban interface residents about ways to keep their houses from burning down. In his day job, he's a wildland/urban interface specialist and a public information representative for the Oregon Department of Forestry.