If you're interested in learning more about Firewise planting, stop by Cornell Farm on August 18th from 10am to 1pm for a free outreach event from the South Skyline Firewise District. They will be offering more information about the plant list below (developed by the Oregon State University Extension Service), as well as resources like Portland Fire and Rescue's free Wildland-Urban Interface (WUI) Home Assessments.

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Although Portland is known for our wet winters, rapidly changing summer conditions in the Pacific Northwest mean hotter and drier summers are putting many homes in the path of wildfires. 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 plants with

• high moisture content
• low amounts of flammable saps, resins, or oils
• self-cleaning tendencies to naturally shed dead leaves, needles, and branches that can act as fuel sources for fire

Of course, not all of these qualities are readily apparent — especially on young plants found at the Nursery — which is why we’re sharing a list of fire-resistant plants suitable for home landscapes here in the Willamette Valley. You can still easily prioritize other important features of your garden design like color, growing conditions, and pollinator-friendliness while protecting your home from wildfire. If you have questions about Firewise plants, our expert gardeners are here to help you make smart decisions for your garden.

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 can serve as a fuel break for potential wildfires. This 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.

1. 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.
2. 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.
3. 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.
4. 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.
5. 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.

Firewise Plant List

The plants in your home landscape can be incredible allies in reducing the risks of fire. The Oregon State University Extension Service has developed this handy list of fire-resistant plants, backed by scientific research on the flammability of the materials. Many of these plants are also drought-tolerant and/or provide excellent habitat for pollinators, but it’s good practice to be mindful about planting varietals that may be invasive to Western Oregon. While there's no such thing as a "fireproof" plant, the plants below have proven to be more resistant to ignition and can act as a natural barrier against wildfires. Many factors go into choosing the right plants for your space – our experienced gardeners at Cornell Farm are here to help your garden flourish!

* = PNW Native Plant or Native Varieties Available
† = Drought Tolerant
X = Some varieties may be invasive - check your area

Groundcovers

Pussytoes (Antennaria species) *†	Wild strawberry (Fragaria species) *X
Rockcress (Arabis species) *†	Sweet woodruff (Galium odoratum) X
False rock cress (Aubrieta deltoidea) †	Dead nettle (Lamium species) X
Basket of Gold (Aurinia saxatilis) †	Silver-edged horehound (Marrubium rotundifolium) *
Miniature mat daisy (Bellium minutum) †	Japanese pachysandra (Pachysandra terminalis) X
Poppy mallow (Callirhoe involucrata) †	Creeping phlox (Phlox subulata) *†
Mahala mat (Ceanothus prostratus) *†	Soapwort (Saponaria ocymoides) *X
Snow-in-summer (Cerastium tomentosum) †X	Stonecrop (Sedum species) *†
Lily of the valley (Convallaria majalis) X	Hens and Chicks (Sempervivum species) *
Iceplant (Delosperma species) †	Creeping thyme (Thymus praecox) *
Sulphur buckwheat (Eriogonum umbellatum) *†	Speedwell (Veronica species) *

Perennials

Yarrow (Achillea species) *†	Candytuft (Iberis sempervirens) *
Hummingbird mint (Agastache species) *	Tall bearded iris (Iris hybrids)
Nodding onion (Alium cernuum) *†	Lavender (Lavandula species) *
‘Star of Persia’ allium (Allium cristophii)	Shasta daisy (Leucanthemum x superbum) *
Ornamental onion (Allium ‘Globemaster’)	Lewisia (L. x longipetala or L. cotyledon) *†
‘Ivory Queen’ allium (Allium karataviense ‘Ivory Queen’ )	Blazing star (Liastris sp.) *
Chives (Allium schoenoprasum)	Asiatic lilies (Lilium spp.) *
Columbine (Aquilegia species) †	Blue flax (Linum perenne) *
Sea thrift (Armeria maritima) *†	Honeysuckle (Lonicera species) X
Orange butterfly weed (Asclepias tuberosa) *	Lupine (Lupinus varieties) *†
False indigo (Baptisia hybrid) *	Evening primrose (Oenothera species) *X
Heartleaf bergenia (Bergenia cordifolia)	Prickly pear cactus (Opuntia spp) *
Mariposa lily (Calochortus species) *†	Oriental poppy (Papaver orientale) *
Sedge (Carex species) X	Beardtongue (Penstemon species) *†
Tickseed (Coreopsis species)	Tall garden phlox (Phlox paniculata varieties) *
Delphinium (Delphinium varieties) X	Jacob’s ladder (Polemonium spp) X
Garden carnation (Dianthus species) X	Solomon’s seal (Polygonatum commutatum)
Pacific bleeding heart (Dicentra formosa) *†	Pasque flower (Pulsatilla patens) *
Coneflower (Echinacea purpurea) *	Prairie coneflower (Ratibida columnifera) *
California fuschia (Epilobium canum syn. Zauschneria) *	Black-eyed Susan (Rudbeckia fulgida or hirta) *
Desert yellow fleabane (Erigeron linearis) *†	Salvia (Salvia sylvestris) *†X
Blanket flower (Gaillardia varieties) *†	Mossy saxifrage (Saxifraga x arendsii)
Cranesbill (Geranium cinereum or striatum) X	Skullcap (Scutellaria species) *†
Prairie smoke (Geum triflorum) *†	Goldenrod (Solidago spp.) †
Sun rose (Helianthemum nummularium) *	Orange globe mallow (Sphaeralcea munroana) *†
Daylily (Hemerocallis species) *	Lamb’s ear (Stachys byzantina) *
Coral bells (Heuchera sanguinea) †	Aster (Symphyotrichum species) †
Hostas (Hosta species)	Fendler’s meadowrue (Thalictrum fendleri) *†
‘Autumn Joy’ Sedum (Hylotelephium herbstfreude) *	Western spiderwort (Tradescantia occidentalis) *

Shrubs

White forsythia (Abeliophyllum distichum)	Mockorange (Philadelphus species) †
Vine maple (Acer circinatum) *†	Ninebark (Physocarpus species) *†
Rocky Mountain maple (Acer glabrum) *†	Western sandcherry (Prunus besseyi) *
Serviceberry (Amelanchier species) *†	Western azalea (Rhododendron occidentale) †
Black chokeberry (Aronia melanocarpa) *	Flowering currant (Ribes species) *†
Barberry (Berberis species) *X	Hardy shrub rose (Rosa species except R. eglanteria and R. multiflora) *†X
Buddleia sterile butterfly bush (Buddleia)	American Cranberrybush (Viburnum trilobum)
Blue-mist spirea (Caryopteris x clandonensis) *	Willow (Salix sp) †X
California lilac (Ceanothus) *	Russian sage (Salvia yangii) *
Kelsey dogwood (Cornus sericea ‘Kelseyi’)	Elderberry (Sambucus sp) †
Red-osier dogwood (Cornus sericea)	Spirea (Spiraea sp)
Shrubby cinquefoil (Dasiphora fruticosa) *	Western spirea (Spiraea douglasii) †
Forsythia hybrids (Forsythia x intermedia) *	Snowberry (Symphoricarpos albus) *†
Oceanspray (Holodiscus discolor) *†	Lilac (Syringa species) *
Native roses (Rosa woodsii, nutkana, and gymnocarpa) *†

Broadleaf Evergreens

Kinnikinnick (Arctostaphylos uva-ursi) *†	‘Carol Mackie’ daphne (Daphne x burkwoodii)
Oregon grape (Berberis aquifolium syn. Mahonia) *†	Salal (Gaultheria shallon) †
Creeping holly (Berberis repens syn. Mahonia) *†	Texas red yucca (Hesperaloe parviflora) *
Point Reyes ceanothus (Ceanothus gloriosus)	Oregon boxwood (Paxistima myrtifolia) *†
Orchid rockrose (Cistus purpureus) *	Pacific rhododendron (Rhododendron macrophyllum) †
Cranberry cotoneaster (Cotoneaster apiculatus) X	Yucca (Yucca species) *

Trees

Amur maple (Acer ginnala) *	Hawthorn (Crataegus species) *X
Bigtooth maple (Acer grandidentatum)	European beech (Fagus sylvatica)
Bigleaf maple (Acer macrophyllum) †	Cascara (Frangula purshiana) †
Red maple (Acer rubrum or Acer x freemanii red maple hybrids)	Thornless honeylocust (Gleditsia triacanthos var. inermis) *
Sugar maple (Acer saccharum)	Kentucky coffee tree (Gymnocladus dioicus)
Red horsechestnut (Aesculus x carnea) X	Walnut (Juglans species)
Red alder (Alnus rubra) †	American sweetgum (Liquidambar styraciflua)
Mountain alder (Alnus tenuifolia) †	Crabapple (Malus species) *X
Serviceberry (Amelanchier species) †	Western sycamore (Platanus racemosa)
Birch (Betula species) X	Quaking aspen (Populus tremuloides ) *†
Western catalpa (Catalpa speciosa) *X	Chokecherry (Prunus virginiana) *†
Common hackberry (Celtis occidentalis) *	Oregon white oak (Quercus garryana) *†
Eastern redbud (Cercis canadensis)	Pin oak (Quercus palustris)
Flowering dogwood (Cornus florida or nuttallii ) †	Red oak (Quercus rubra) *
Common smoketree (Cotinus coggygria) *	‘Purple Robe’ locust (Robinia pseudoacacia) X
Japanese tree lilac (Syringa reticulata)

Get Connected to a Firewise Community

If you want to get serious about protecting your 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. Firewise Neighborhoods have successfully acted as fire breaks due to the collaborative efforts of the community.  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!

If you’re building a Firewise garden with plants from Cornell Farm, tag us on social media and use the hashtags #FirewiseLandscape and #OSUExtension to follow along with other homeowners from across the region and the nation.