By Renate Tilson

Homeowners are interested in creating a garden that is aesthetically pleasing, with variations in color and textures that complement their home. However, if your house is located near a forest or grasslands, you should consider the flammability of your plant choices in order to reduce fire risk. With the fire season nearing and summer and fall gardening opportunities ahead, it’s prime time to consider the most desirable choices for your landscape setting.

First, think of the first 30 feet from your house as a defensible zone—a fire-resistant space. This area closest to your house should be heavy on paths, patios, and other hardscapes. Walkways and retaining walls have great value, acting as barriers to quick-spreading fire. Do away with potential fuel and fire hazards by removing dead plants, trees, and underbrush within 30 feet of your home and keeping grass short to within 100 feet. 

Emphasize low-growing, non-woody plants kept green with an irrigation system during the fire season, if necessary. While no plants are completely fireproof, ensuring that your plants are well watered will at least help your vegetation resist burning. This may be incentive to invest in a good drip irrigation or sprinkler system to be sure plants are deeply and regularly watered, without wasting water in the process. 

Plants with more water stored in their shoots and leaves are a safer bet, and fire-resistant lawn grass and groundcovers require higher temperatures to ignite. Such plants include members of the succulent family, ground covers, bedding plants, and perennials, such as yarrow, gazania, or poppies. Even though fire-resistant plants can be damaged or killed by fire, at least their foliage and stems won’t contribute to the fuel.

When thinking about how to slow the movement of a wildfire, space is key. Design your plantings in clusters, with adequate space between them, rather than packing the garden with plants standing shoulder to shoulder. When planting fire-resistant trees, such as maple, chestnut, or alder, space them 30 or more feet apart so flames can’t jump from one crown to the next. Poplar and cherry, which hold a fair amount of moisture, are also desirable fire-resistant choices.

Trim low-hanging limbs 15 feet or more off the ground, and cut back branches 15 to 20 feet from your house. In wooded areas, remove dry, weak, or diseased trees and thin the healthy ones. Eliminate fire “ladders,” which are plants of different heights that form a continuous fuel supply from the ground up into the tree canopy.

Avoid juniper and other evergreens, which, although popular, are highly flammable. This family contains resins that make them susceptible to fast burning. You should also avoid shrubs, such as sagebrush or scotch broom, which contain volatile oils, flammable creosote, and waxes. Choose foundation plants that are proven to stand up well against fire, including salal, mahonia, hedging roses, or cotoneaster. Keep them well watered or, if you lack water, simply cut them back during the dry months.

Get a fire-resistant plant list from the OSU Extension Service, which also includes smart tips on what, how, and when to plant. Throughout the season, continue to thin, prune, mow, and rake your garden regularly to minimize fuel and keep it fire resistant this fire season and all the ones to follow.