Although Portland is known for our wet winters, the dry heat of our summers means that wildfire season is still a reality we have to contend with. The good news for gardeners is that our home landscaping can provide the first line of defense for our homes, our communities, and our urban forests!

Choosing Fire-Resistant Plants

All of the plants in the photo above have one thing in common: They are fire-resistant! Plants like these are fundamental to a firewise landscape because they won't add intensity to the flames in the unfortunate event of a fire. Desirable qualities to look for are leaves and stems with a high moisture content and that contain low amounts of flammable saps, resins, or oils, as well as plants that have a tendency to be self-cleaning. (Dead leaves, needles, and branches that regularly remain attached to a plant or accumulate within it as it ages are a fire hazard, and plants known to exhibit these traits should be avoided in the areas closest to your home.) Of course, not all of these qualities are readily apparent — especially on young plants found at the Nursery — which is why we've put together the following list of fire-resistant plants suitable for home landscapes here in the Willamette Valley.

* = PNW Native Plant or Native Varieties Available
† = Evergreen or Evergreen Varieties Available

Perennials & Groundcovers

Rock Cress (Aubrieta deltoidea)
Yarrow (Achillea millefolium)*
Monkshood (Aconitum spp.)*
Carpet Bugleweed (Ajuga reptans)
Lady's Mantle (Alchemilla mollis)
Narrowleaf Onion (Allium amplectens)*
Nodding Onion (Allium cernuum)*
Chives (Alllium schoenoprasum)
Pearly Everlasting (Anaphalis margaritacea)*
Windflower (Anemone blanda)
Columbine (Aquilegia spp.)*
Rockcress (Arabis spp.)†
Kinnikinnick (Arctostaphylos uva-ursi)*†
Sea Thrift (Armeria maritima)*†
Wild Ginger (Asarum caudatum)*
Basket of Gold (Aurinia spp.)
Heartleaf Bergenia (Bergenia cordifolia)
Bellflowers (Campanula spp.)
Sedges (Carex spp.)*†
Snow in Summer (Cerastium tomentosum)
Chrysanthemum (Chrysanthemum spp.)
Lily-of-the-Valley (Convallaria majalis)
Tickseed (Coreopsis spp.)
Cranberry Cotoneaster (Cotoneaster apiculatus)†
Iceplant (Delosperma spp.)†
Larkspurs (Delphinium spp.)*
Dianthus (Dianthus spp.)
Purple Coneflower (Echinacea purpurea)
California Fuchsia (Epilobium canum)
Western Wallflower (Erysimum asperum)*
Yellow Monkey Flower (Erythranthe guttata)*
Strawberry (Fragaria spp.)*†
Blanket Flower (Gaillardia spp.)*
Sweet Woodruff (Gallium odoratum)†
Cranesbill (Geranium spp.)*
Prairie Smoke (Geum spp.)*
Sun Rose (Helianthemum nummularium)†
Daylilies (Hemerocallis spp.)
Coralbells (Heuchera spp.)*†
Hostas (Hosta spp.)
Candytuft (Iberis sempervirens)†
Irises (Iris spp.)*†
Red-Hot Poker (Kniphofia spp.)*
Dead Nettle (Lamium spp.)
Shasta Daisy (Leucanthemum x superbum)
Lupine (Lupinus spp.)*
Four O’clock (Mirabilis spp.)
Wild Bergamot (Monarda fistulosa)
Evening Primrose (Oenothera spp.)
Japanese Pachysandra (Pachysandra terminalis)†
Oriental Poppy (Papaver orientale)
Virginia Creeper (Parthenocissus quinquefolia)
Beardtongues (Penstemon spp.)*
Russian Sage (Perovskia atriplicifolia)
Phlox (Phlox spp.)†
Jacob's Ladder (Polemonium spp.)
Pasque Flower (Pulsatilla patens)
Prairie Coneflower (Rudbeckia columnifera)
Black-eyed Susan (Rudbeckia hirta)*
Sage (Salvia spp.)
Saxifrage (Saxifraga hirsuta)†
Stonecrop (Sedum spp.)*†
Hens and Chicks (Sempervivum spp.)†
Goldenrod (Solidago spp.)*
Lamb's Ear (Stachys byzantina)†
Asters (Symphyotrichum spp.)*
Meadow Rue (Thalictrum fendleri)*
Thyme (Thymus spp.)†
Western Spiderwort. (Tradescantia occidentalis)
Speedwell (Veronica umbrosa)
Yucca (Yucca spp.)†

Shrubs

Red Buckeye (Aesculus pavia)
Serviceberry (Amelanchier spp.)*
Beautyberry (Callicarpa spp.)
Heather (Calluna spp.)†
Sweetshrub (Calycanthus spp.)*
Trumpet Vine (Campsis radicans)
Bluebeard (Caryopteris spp.)
Point Reves Ceanothus (Ceanothus gloriosus)†
Buttonbush (Cephalanthus occidentalis)
Rockrose (Cistus x purpureus)†
Sweet Pepperbush (Clethra alnifolia)
Red-Osier Dogwood (Cornus sericea)*
Daphne (Daphne spp.)†
Cascara (Frangula purshiana)*
Salal (Gaultheria shallon)*†
Witch Hazel (Hamamelis virginiana)
Oceanspray (Holodiscus discolor)*
Smooth Hydrangea (Hydrangea arborescens)
Winterberry (Ilex verticillata)
Virginia Sweetspire (Itea virginiana)
Honeysuckle (Lonicera spp.)*
Oregon Grape (Mahonia spp.)*†
Prickly Pear Cactus (Opuntia spp.)†
Oregon Boxwood (Paxistima myrtifolia)*†
Mock Orange (Philadelphus spp.)*
Shrubby Cinquefoil (Potentilla fruticosa)*
Sand Cherry (Prunus besseyi)
Pacific Rhododendron (Rhododendron macrophyllum)*†
Western Azalea (Rhododendron occidentale)*
Sumac (Rhus spp.)
Gooseberry and Currants (Ribes spp.)*
Roses (Rosa spp.)*
Willows (Salix spp.)*
Elderberry (Sambucus spp.)*
Cotton Lavender (Santolina chamaecyparissus)†
Spirea (Spiraea spp.)*
Lilac (Syringa spp.)
Blueberries (Vaccinium spp.)†
Viburnum and Blackhaw (Viburnum spp.)*†

Trees

Maples (Acer spp.)*
Horsechestnut (Aesculus hippocastanum)
Alders (Alnus spp.)*
Pawpaw (Asimina triloba)
American Hornbeam (Carpinus caroliniana)
Catalpa (Catalpa speciosa)
Redbuds (Cercis spp.)*
Fringe Tree (Chionanthus virginicus)
Flowering Dogwood (Cornus florida)
Black Hawthorn (Crataegus douglasii)*
Beeches (Fagus spp.)
Ash (Fraxinus spp.)*
Kentucky Coffee Tree (Gymnocladus dioicus)
Walnut (Juglans spp.)
Western Larch (Larix occidentalis)*
Sweetgum (Liquidambar styraciflua)
Crabapple (Malus spp.)*
Ponderosa Pine (Pinus ponderosa)*†
Quaking Aspen (Populus tremuloides)*
Chokecherry (Prunus virginiana)*
Oregon White Oak (Quercus garryana)*
Willow (Salix spp.)*
Mountain Ash (Sorbus aucuparia)
Bald Cypress (Taxodium distichum)
American Linden (Tilia americana)
American Elm (Ulmus americana)

While there's no such thing as a "fireproof" plant, the plants above have proven to be more resistant to ignition and can act as a natural barrier against wildfires.

Firewise Landscaping Techniques

Your garden provides a transition between your home and the surrounding natural landscape — especially if you live in a forested area. With the right landscaping practices, this transitional area can act as a "defensible space" to slow or halt the spread of fire. A well-maintained zone of at least 30 feet around your home that can serve as a fuel break for potential wildfires, which will not only help to limit the spread of flames directly, but also reduce the threat of radiant heat igniting the structure of your home. In addition to selecting fire-resistant plants, consider the following landscape techniques for your firewise landscape.

Choose Fire-Resistant Mulches and Hardscapes: Incorporating non-flammable materials like rocks, gravel, and concrete into your landscape design can help to reduce the amount of fuel available to fires — especially in the defensible space around your home. In place of traditional wood mulches, consider gravel or rock alternatives for your foundation planting.
Keep Up With Garden Cleanup: You want to limit flammable materials in your defensible zone, including dead plant material. Even in the further reaches of your property, it's important to staying on top of brush areas. For instance, when left unchecked, invasive blackberry can overwhelm and shade out native plants, creating dense thickets filled with dead wood and leaves that can fuel fires.
Stay on Top of Pruning: It's always best practice to keep dead and dying branches pruned out of trees and shrubs, but this is especially important when it comes to firewise landscaping, as this limites the fuel available to fires. In some cases, it may be appropriate to prune the limbs of mature trees up to 10 feet above the ground to prevent fire from climbing their trunks. To limit the risk of fire spreading to your home, you should also consider removing any branches that overhang your house.
Properly Space Plants: Avoid planting shrubs and trees too close together. A good rule of thumb is 25 feet of distance between trees, 3 or more feet for shrubs, and at least a foot between perennials. (Some fire-resistant shrubs like our native salal and Oregon grape can be planted more closely.) Adequate spacing helps prevent the rapid spread of fires when flames are easily able to jump from one plant to another.
Keep Plants Well-Watered: There's a reason that wildfire season coincides with the drought conditions of summer. Dry, stressed plants are simply more vulnerable to catching fire than their well-hydrated counterparts, making adequate irrigation an important part of a firewise landscape.

Get Connected to a Firewise Community

If you want to get serious about protecting our community from the risks associated with wildfires, consider joining a local group like Firewise USA. This nationwide program provides resources to help communities reduce the risk of wildfires at the local level, and multiple Firewise Neighborhoods have been created in and around Portland, including the Forest Park area. Portland residents can also sign up for a free Wildland Urban Interface (WUI) Assessment from Portland Fire & Rescue, which provides recommendations for wildfire risk mitigation that are tailored to your home and property. Other good resources for finding fire-resistant plants and landscaping techniques include the PNW Extension Guide to Fire-Resistant Plants for Home Landscapes, and the Guide to Fire-Resistant Native Plants for Western Multnomah County from Tualatin Valley Soil & Water Conservation District, which we consulted when writing this blog post.

Remember, fire-resistant plants and landscaping techniques are not foolproof measures, but they can greatly improve the chances of preserving your property in the unfortunate event of a wildfire. We invite you to consult with local experts and the resources provided above for more specific recommendations based on your location. Stay safe and be proactive in creating a fire-resistant landscape!

(Wildfire imagery courtesy of the Pacific Northwest Region of the U.S. Forest Service.)