Fire-Resistant and Drought-Tolerant Shrubs
Landscaping for Wildfires and Drought
I was just outside of Tucson, Arizona, in 2003, when the Aspen Fire started.
The house where I was staying was nestled in the foothills on the north side of the Catalina Mountains. Over a few smoldering days in June, I saw the wildfire crest the mountains’ peaks and creep down the north face of the range, burning like the lit end of a cigarette.
The people I was visiting were lucky. They didn’t have to evacuate. Hardworking firefighters contained the fire before it was anywhere close to threatening their home.
It could’ve gone differently.
In the face of a wildfire, there’s only so much that desert homeowners like my former hosts can do. But one step that professionals encourage homeowners in dry climates to take before a fire starts is to use fire-resistant and drought-tolerant landscape design.
Why Does Landscape Design Matter?
Homeowners everywhere, especially in the desert, understand the benefits of drought-tolerant landscaping. It conserves water. That’s good for the environment and good for their finances.
But living in a dry area requires more than just drought-tolerant landscaping. It requires fire-resistant landscaping.
Some shrubs and bushes are naturally better suited to withstand drought and fire. Planting these at safe distances on your property can make it harder for a fire to spread.
Smart landscaping with fire-resistant and drought-tolerant shrubs and other plants not only can save you money in the long run. It can reduce the risk of loss to your home and nearby structures in a fire.
What Are Drought-Tolerant and Fire-Resistant Plants?
It’s important to know that drought tolerance and fire resistance are not the same.
Drought-tolerant plants require very little water. They’ve adapted to survive in dry conditions.
Fire-resistant plants don’t readily catch fire. If they do catch fire, they won’t significantly add to an existing fire because they’re not good fuel.
Keep in mind, “fire-resistant” does not mean “fire-proof!” There is no such thing as a plant that won’t catch fire. There are only plants that are more difficult to set on fire.
So what kinds of plants are those?
Well, some fire-resistant plants have qualities in common with drought-tolerant plants:
- Extensive root systems
Both types of plants need roots that either grow deeply or grow across a large distance to find water.
- Minimal foliage
Plants lose water through their leaves. You won’t find many drought-tolerant or fire-resistant plants that have the large, dense leaf canopy of an oak or a maple.
- Leaves that retain moisture
Fire-resistant and drought-tolerant plants still have leaves, though. Their leaves are modified in ways that help them hold on to moisture. They might be waxy, small, or even needle-like. The spines on a saguaro cactus, for example, are actually leaves.
- Low resin content
Some plants produce substances like resin (think of the sticky amber liquid you’ve seen on a cut pine tree). Resins are highly flammable. They won’t be found in heavy concentrations, if at all, in drought-tolerant or fire-resistant plants.
As F.C. Dennis, a retired Staff Forester for the Colorado State Forest Service, wrote, “In some cases, there is a strong correlation between drought tolerance and fire resistance.”1 This makes sense since both types of plants survive in extreme conditions.
Which Shrubs Are Good for Landscaping?
Before you start working, don’t just plant any shrub that’s marked as drought-tolerant or fire-resistant.
It’s crucial to plant shrubs that can thrive in your local climate. This is your USDA hardiness zone. Check with your local garden center or nearest university extension office to find out what your area’s hardiness zone is.
Also, check that the bushes you choose are not considered invasive! An invasive plant is a plant that doesn’t naturally grow in your area. Once an invasive plant takes root, it often dominates and outgrows native plants.
With those tips in mind, you can easily find lists of fire-resistant or drought-friendly landscaping plants. Below are some favorites that grow as bushes or shrubs:
- Sage or salvia (several species)
- Creeping holly
- Sumac (several species)
- Lilac (several species)
- Hardy shrub rose
- Oregon boxwood
- Blue mist spirea
Which Plants Are Not Fire Resistant?
The short answer is - a lot of them. However, the following plants are some of the most fire-prone. Avoid using these in fire-smart landscape design:
- Juniper: its branches often dry out
- Palm trees and eucalyptus: they drop dry fronds and leaves
- Conifer trees (pine, cedar, fir, etc.): they produce a highly flammable resin
How Do I Design a Drought-Tolerant Landscape?
When planting drought-tolerant plants, place plants that have similar water and sunlight requirements in the same area, this will help your plants thrive while allowing you to water them efficiently.
How Do I Design a Fire-Resistant Landscape?
According to experts, even fire-wise shrubs should be planted farther from the home than you might think. Some landscaping and university professionals2 recommend a minimum distance of 15 feet away from a house or any structures.
The reason for this is simple: the closer the shrub, the easier it is for flames to spread from the bush to your home.
Instead, save the space closer to your home for other landscaping elements. Rocks, short plants, and raised garden beds are best placed at a medium distance from the house (between five feet and 15 feet away).
Fill the five feet immediately surrounding your home with non-flammable elements. This space is ideal for walkways and paving stones. Avoid placing plants or other flammable landscaping items in this five-foot perimeter.
Landscaping: Less Is More
One of the reasons the Aspen Fire spread so quickly was that the forest landscape at the top of the Catalina Mountains was dry and overgrown.3 It provided plenty of fuel to drive the wildfire.
There are reasons why desert landscaping often looks minimalist. Conserving water and reducing the risk of fire are two of them.
Keeping shrubs and other plants decently spaced, adequately watered, and properly pruned maintains their health. It prevents your landscaping from becoming dense and parched, like the forest the Aspen Fire consumed.
But you don’t have to live in a desert to use fire-resistant and drought-tolerant landscaping ideas. Any homeowner can put them into practice to create landscaping that’s attractive and safe.