FIRE-RESISTANT PLANTS: PNWCG

fire-resistant plants Oregon has many wildfire-prone areas. In these places, fires are a natural part of the changing landscape. As homes are built in these areas, though, special precautions must be taken by homeowners to protect their property. Installation of fire-resistant roofing is critical to preventing firebrands from igniting a roof fire. Well maintained fire-resistant vegetation and irrigated landscape are also critical within proximity of a home.

These actions DO NOT ensure that a home will survive a wildfire, but they do provide for a good chance of structural survival. Implementation of FireFree [firefree.org] and FireWise [firewise.org] activities can also significantly improve chances of a home surviving a wildfire.

Fire-resistant vegetation: When landscaping around a home, most homeowners are interested in creating a landscape that is aesthetically pleasing and complements their home, with variations in color, texture, flowers, and foliage. If your home is sited in or adjacent to forests or rangeland, you should also consider the flammability of plants within your home landscape. Flammable plant material in your landscape can increase the fire risk around your home. The 1991 Oakland Hills Fire in California is a prime example of how flammable plant material (e.g. Eucalyptus trees) can act as fuel and contribute to the intensity of a wildfire. More than 3,000 homes were destroyed in that devastating wildfire.

Taking action: Homeowners should take active steps to minimize or reduce the fuel and fire hazard around their homes, including planting fire-resistant plants. Good placement and on-going maintenance of fire-resistant trees, for example, can help protect your home by blocking intense heat.

a surviving home Making choices: There is a wide array of trees and other plants to choose for your landscape that are both attractive and fire-resistant. This publication provides a diverse list of plant material divided into sections for groundcovers, perennials, evergreen shrubs, deciduous shrubs, and conifer & deciduous trees.

Annuals: Annuals can be part of a fire-resistant landscape if well watered and well maintained. We have not listed all of these because of the large number of annuals available in the region.

Turf: A well maintained lawn can be included in a fire-resistant landscape and serves as an effective fuel break. For more information on lawn care and maintenance, check out available publications from your local OSU Extension Service.

A Caution About Bark Mulch: Bark mulch is often used in home landscapes. However, fire brands from a wildfire, along with cigarettes or dumped charcoal or fireplace ashes, can ignite dry bark mulch, conveying the fire to your home. If you landscape with bark mulch up against your home, make sure it remains moist to prevent ignition.

Fire-resistant plants are plants that don't readily ignite from flames or other ignition sources. Though fire-resistant plants can be damaged or killed by fire, their foliage and stems don't contribute significantly to the fuel -- and therefore the fire's intensity. "Fire-resistant" does not mean fire-proof. Plants that are fire-resistant have the following characteristics:

Leaves are moist and supple.
Plants have little dead wood and tend not to accumulate dry, dead material within the plant.
Sap is water-like and does not have a strong odor.

Most deciduous trees and shrubs are fire-resistant. However, it's important to remember that even fire-resistant plants can burn, particularly if they are not maintained in a healthy condition.

In contrast, plants that are highly flammable have these general characteristics:

Contain fine, dry or dead material (twigs, needles, and leaves) within the plant.
Leaves, twigs, and stems contain volatile waxes, terpenes, or oils.
Leaves are aromatic (strong smell when crushed).
Sap is gummy and resinous and has a strong odor.
May have loose or papery bark.

Both ornamental and native plants can be highly flammable. One highly flammable ornamental shrub often planted in home landscapes is ornamental juniper. Highly flammable native shrubs include bitterbrush, manzanita, sagebrush, and ceanothus. Avoid planting these plants around your home.

-Adapted from University of California
Cooperative Extension Hortscript, 1996, No. 18.

How this list was developed: This list was developed by evaluating fire-resistant plant lists developed for other regions and screening the scientific literature on plant flammability. Included in this list are plants adapted to grow in Oregon in either irrigated or non-irrigated landscapes. key to plants However, most of the plants on this list require some level of irrigation to survive during the dry summer months, particularly in central and eastern Oregon.

The plants in this publication are adaptable in all regions of Oregon unless otherwise marked with an identifying orange symbol. Plants marked with these symbols are suitable only for the regions specified.

GROUNDCOVERS : PERENNIALS : EVERGREEN SHRUBS
DECIDUOUS SHRUBS : CONIFER & DECIDUOUS TREES

NOTE: If you belong to a homeowners association, be sure to check with them before deciding on which plants to purchase for your yard.

Figure 1 landscape layout

Disclaimer: The purpose of this document is to provide homeowners with guidance on ways to landscape their property with fire-resistant vegetation to help reduce losses from wildfire damage. It contains suggestions and recommendations based on professional judgment, experience, and research -- and is intended to serve only as a guide. The authors, contributors, and publisher disclaim all warranties and guarantees with respect to the information in the document and assume no liability nor responsibility with respect to the information.

Plant descriptions and availability: For detailed descriptions of the plants on this list, consult your local nurseries or refer to the Sunset Western Garden Book and the A-Z Encyclopedia of Garden Plants. These publications can be obtained at local bookstores or libraries or nurseries. If you are unable to find some of these plants locally, check out the Oregon Association of Nurserymen's website for plant availability at nurseryguide.com where you can search by plant and find nurseries that carry it.

Help us identify other fire-resistant plants: If you know of other fire-resistant plants suitable for Oregon, let us know. We will research your plant, and if it fits the criteria, we will add it to the list. Contact Stephen Fitzgerald at (541) 548-6088, x16 or Stephen.Fitzgerald@orst.edu or Amy Jo Waldo at (541) 548-6088, x12 or Amyjo.Waldo@orst.edu

Photo Acknowledgments: The photos in this publication have been gathered from a wide variety of sources. We would like to recognize the following groups and individuals for their helpful contributions:

ForestryImages.org
Pat Breen, Oregon State University
Brother Alfred Brousseau, St. Mary's College of California
Kenneth M. Gale, Mosaic Tile Company
William R. Hewlett, California Academy of Sciences
Robert Potts, California Academy of Sciences
Dave Powell, USDA Forest Service
Jil M. Swearingen, USDI National Park Service
Dean Wm. Taylor, California Academy of Sciences
Amy Jo Waldo & Stephen Fitzgerald, OSU Extension Service
Charles Webber, California Academy of Sciences
Colorado Springs Utilities
Paul Wray, Iowa State University

The Oregon State University Extension Service provides research-based information to Oregon residents in the areas of Agriculture, Forestry, Family and Community Development, 4H and Youth Development, and Marine and Watershed Resources.