It might not seem like plants would do much to protect your home from a wildfire. However, they can be a very effective line of defense under the right circumstances. Keep reading to learn how to use firescaping to make your home safer.
What is Firescaping?
Firescaping is essentially landscaping to prevent fire damage. It includes designating firesafe zones, choosing fire-resistant plants, and making spaces that slow or stop a spreading fire by starving it of fuel.
Just like different locations have different fire risks, some homes are a bit harder to firescape than others. If you live on a flat plot of land surrounded by hardpan desert with few plants, you probably don’t need much extra firescaping.
However, if your home is at the top of a hill, facing into prevailing winds, and surrounded by dense forest, it’s worth putting some serious effort into your firescaping. Hot smoke flows uphill, and a fire can spread twice as fast up a 30% slope compared to flat ground. Add in fir trees or creosote bushes, both of which burn well, and it’s easy to see why firescaping is necessary.
Creating Firescaping Zones
An ideal firescaping solution will slow a fire on the outskirts of your lot and stop it close to the house. To meet that goal, you’ll usually need two different zones.
Zone 1
Zone 1 usually extends 30 feet from the house and up to 50 feet in high-risk areas. Most of your attention should go toward this zone.
Remove all dead or dry plants in the radius of the zone, keep tree branches trimmed back, make gravel or rock gardens, and plant only highly fire-resistant plants here.
Zone 2 and Beyond
Zone 2 extends 30 to 50 feet from the house. Here, you have some more flexibility in what you plant, but you still need to choose plants that are somewhat fire-resistant. Keep shrubs within the zone thinned, and trim tree limbs to at least 10 feet off the ground.
Beyond Zone 2, focus on controlling erosion and promoting a diversity of native plants. Ideally, any approaching wildfire should die or slow down dramatically once it reaches this area.
The Principles of Firescaping
These basic guidelines will help you create a fire-resistant landscape, even if you’re not an expert gardener.
In all cases, choose plants that won’t feed an oncoming fire. Space out your planting beds so fires are harder to spread, and keep your landscape clean and healthy so it stands up to heat.
Keep Fuel Away
In Zone 1, near your house or other structures, landscaping choices are critical. Within 5 feet of your house, use only non-combustible material such as pavers or gravel and low-growing, fire-resistant plants such as turf grass or flowers. Keep composted wood chips out of this area. This material smolders rather than burns and can pose a fire hazard you don’t notice until it’s too late.
Anything you plant elsewhere in Zone 1 should be highly fire-resistant. These plants might burn up completely, but they don’t create flames that could spread. They also catch and extinguish firebrands, or burning material falling from elsewhere.
Focus on native plants that have evolved to withstand the wildfires in your area. Choose low-growing species that retain water and contain little oil or resin. Deciduous trees, which hold more water and provide less fuel than evergreens, are good bets. Slow-growing plants with moist, soft leaves are better than fast growers with leathery leaves.
A few good picks for this zone include these:
- Turf grass
- Most vegetables
- Cacti and succulents
- Periwinkle (C. roseus)
- Star jasmine (T. jasminoides)
- Oleander (N. oleander)
- Ice plant (Aizoaceae)
For Zone 2, try the following plants:
- California lilac (Ceanothus)
- Ivy geranium (P. peltatum)
- Sage (S. officinalis)
- Yucca
- Lantana
Avoid both conifer and broadleaf evergreens, particularly pines, spruce, fir, cypress, juniper, rhododendron, and eucalyptus. The oils and resins these trees produce make excellent hot-burning fuel. Ornamental grasses and climbing plants, particularly honeysuckle, are best avoided.
So are scented plants, which get their scent from volatile oils that ignite easily. Even some palms and their fronds are too flammable for use in firescaping.
Give Your Plants Space
Where you put each type of plant is as important as the plant species itself. Plant trees so their canopies will be 10 feet apart after reaching mature height. Their limbs should be 10 feet away from your chimney, smaller roofs, and power lines.
Create island planting beds with plenty of space in between. This helps slow the spread of fire. Keep vertical layers of plants well separated to prevent “fuel ladders,” where flames spread from shorter plants to taller ones. For example, use groundcover plants under trees rather than shrubs or tall flowers.
To add beauty to your landscape and help it withstand fire, apply a 3-inch layer of mulch to your flowerbeds and around trees and shrubs. Mulch holds moisture in the soil, which slows down the spread of fire. It also controls soil temperatures and weeds, so plants stay healthier and will be less likely to burn. Only non-combustible materials are safe with 5 feet of the house, but outside that, other common mulches such as pine bark or leaf litter are acceptable.
Find out where firefighters would access your property if need be and keep that area clear of vegetation.
Make Fuel Breaks
A vital component in every firescape design, “fuelbreaks” are buffer zones designed to deprive a spreading fire of fuel in order to slow its spread. Any area with little combustible material can work.
Functional hardscaping features such as masonry patios, driveways, and walkways are often the most practical options. A lawn is a reasonably good firebreak, but if turf grass is too thirsty for your drought-prone area, try a groundcover or low-growing native grass instead. These are easier to keep green throughout the fire season.
Beyond this, a little creativity goes a long way. Consider creating a rock garden with a few artfully arranged boulders surrounded by gravel mulch or an artificial dry streambed. A line of riprap can also work.
If your home could use a little more privacy as well as fire protection, build a wall made of brick, cement or another non-combustible material. Water features, such as ponds and streams, are also helpful for stopping fires. A simple reflecting pool could go a long way toward protecting your home.
While bare ground does slow down fire, it’s not recommended in firescaping because it contributes to erosion.
Keep It Green
A healthy landscape is less vulnerable to fire. To keep yours healthy, regularly remove debris on the ground such as fallen leaves and branches. Trim back tree branches or other plants that threaten to overhang your roof. Prune your trees and shrubs using the approach recommended for the species. Incorrect pruning or worse, shearing, causes plants to produce faster, but weaker growth, making them more flammable.
Keep your landscape well irrigated. Drip irrigation, while environmentally friendly, doesn’t keep plants’ leaves wet enough to resist heat. When a wildfire is approaching, you might not have the water pressure you need to wet down your planting areas, so water regularly. If frequent droughts in your area make this impractical, base your landscape on features that don’t need much watering, such as rock gardens.
