The threat of Colorado wildfires can feel apocalyptic. But with the right landscaping strategy, you can create a fire-resistant landscape that helps minimize a fire’s spread and creates a safe area for firefighters to protect your home.
The following five fire-resistant landscaping ideas for Denver won’t guarantee your home survives a wildfire, but they will help increase its chances.
- Create defensible space
- Grow fire-resistant plants
- Apply fire-resistant mulch
- Build hardscapes
- Learn to love metal
Here are the ways you can give your home a fighting chance against a raging fire.
1. Create defensible space
Wildfires are unpredictable. But you have the power to prepare your home by turning your landscape into a defensible space.
According to the Colorado State Forest Service, defensible space is the area around your home that has been made to reduce fire hazards. When it comes to your landscape, you must carefully plan sectioned areas that will slow the spread of fire. Creating defensible space also helps prevent the fire from spreading to your neighbors’ homes.
The Forest Service recommends establishing three zones around every structure on your property. These zones are:
Zone 1 (Extends a minimum of 15 to 30 feet from the structure): This is the area closest to the structure. It requires the most work to reduce fire hazards. Because fires move faster uphill, increase the distance 5 feet or more in areas downhill from the structure.
- Remove all flammable vegetation from this zone.
- Plant nothing within the first five feet of the structure.
- Install a non-flammable ground cover, such as rocks, to help prevent the fire from coming in direct contact with the structure.
- Prune any plants growing in this zone.
- Remove all branches, leaves, and debris, including on the roof and in the gutters.
- Do not store woodpiles or combustible materials in this zone.
- Do not grow any trees in this zone. If trees already exist, it’s best to remove them.
Zone 2 (Extends at least 100 feet from the structure): This area is the transitional space between zone 1 and zone 3. If you live on a hill, you may need to increase this zone up to 150 feet.
- Ensure trees and large shrubs in this zone are separated by at least 10 feet between the crowns. The 10-foot separation is not between the trunk’s base but instead between the longest branches. You might need to remove trees and shrubs to achieve this separation.
- Remove tree branches off the trunk to 10 feet off the ground or ⅓ the tree’s height (whichever is less) to help prevent flames from climbing up the tree.
- Remove dead, dying, or diseased trees in this zone.
Zone 3 (Expands past 100 feet from the structure): This is the space farthest from the structure. It typically targets Colorado homes near wooded areas that require a form of forest management.
- A local Colorado State Forest Service forester can help you manage this zone.
Advantages of creating defensible space: Not only does creating a defensible landscape increase your home’s chances against a fire, but it also creates a safer space for firefighters to help protect your home. Firefighters are more likely to target homes with defensible spaces because they have a greater chance of being saved and are less likely to endanger their lives.
Pro Tip: Keep in mind that the minimal distances listed above for each zone may vary depending on the slope of your land.
2. Grow fire-resistant plants
There’s no such thing as a fireproof plant. But there are fire-resistant plants that can help slow the spread of fire. Many fire-resistant plants are salt-tolerant and drought-tolerant.
Before you start growing fire-resistant plants around your property, here are a few tips to keep in mind that will better protect your home:
- Spacing is more critical than the type of fire-resistant plant you grow. Ensure there is sufficient space between all plants to help mitigate the flames. For shrubs, that means planting them a distance that is twice their height. A 2-foot shrub shouldn’t be any closer than 4 feet from another shrub. For trees, that means a 10-foot distance between the longest branches.
- If planting in groups, avoid grouping the plants in the masses but instead in small clusters.
- Grow plants that retain moisture. That also means watering your plants regularly so that they don’t go dry.
- Maintenance is essential. Remember to remove any dead branches, pine needles, and dead leaves littering the landscape. Dead and dry plant material is kindling for a fire.
What if I’m growing plants on a slope? When growing plants on a hill, you’ll need to increase the distance between the plants (or the grouped clusters). The reason for expanding the space is because fire travels faster uphill. The California Department of Forestry and Fire Protection makes the following distance recommendations:
|Slope size||Appropriate shrub distance||Appropriate tree distance|
|Flat to mild slope (less than 20%)||2 times the shrub’s height||10 feet|
|Mild to moderate slope (20% to 40%)||4 times the shrub’s height||20 feet|
|Moderate to steep slope (greater than 40%)||6 times the shrub’s height||30 feet|
The Colorado State University Extension recommends the following fire-resistant plants:
- Lady’s mantle (Alchemilla sp.)
- Nodding onion (Allium cernuum)
- Pearly everlasting (Anaphalis margaritacea)
- Spring beauty (Claytonia lanceolata)
- Rockcress (Arabis sp.)
- Prairie sage (Artemisia ludoviciana)
- Smooth aster (Aster laevis)
- Mariposa lily (Calochortus gunnisonii)
- Jupiter’s beard (Centranthus ruber)
- Hardy yellow ice plant (Delosperma nubigenum)
3. Apply fire-resistant mulch
Even mulch can help combat fire. It helps moisture-loving plants conserve water and reduces weed growth (weeds are also fire kindling).
But the wrong mulch can be a significant fire hazard.
The most flammable mulches to avoid are:
- Shredded rubber
- Pine bark
- Pine needles
- Cedar bark
Inorganic mulches typically have superior fire resistance, such as rocks and gravel.
According to Washington State University, coarse-textured organic mulches, such as wood chips, are the least flammable organic mulches.
In a mulch combustibility study performed by the University of Nevada Cooperative Extension, the composted wood chip sample was the least combustible.
4. Build hardscapes
What are hardscapes, and why does your Denver landscape need them? Hardscapes refer to the non-living materials incorporated into a landscape design, such as patios, walkways, retaining walls, and decorative fire pits.
Hardscaping materials like rock and brick help minimize the spread of fire. For example, installing hardscape edging around your plant beds or a walkway in the garden can help prevent flames from spreading to various plant clusters.
Large hardscape areas, such as a patio, create a protective zone right around the outside of your home. They also help create fire-resistant zones for firefighters. If your landscape only has vegetation, the likelihood of firefighters finding a safe, open space to protect your home decreases.
5. Learn to love metal
Wooden structures like gazebos, pergolas, and fences can look beautiful in the landscape. Wood comes in many beautiful colors, attractive textures, and even has a warm scent. But these structures will burn to the ground in a fire and even spread flames.
Metal is a superior fire-resistant alternative. Metal structures bring sheer beauty to a landscape without the threat of a fire hazard, and they’re low maintenance, too. On top of being highly flammable, wooden structures are also susceptible to rot, decay, and insects. With metal structures, you just have to routinely pressure wash them to maintain their new appearance, and they last much longer than wooden structures.
Why does my Denver home need fire-resistant landscaping?
Your Denver home might not be sitting in the neighboring mountains, but that won’t stop a raging fire from barreling down the Rocky Mountain foothills. Denver’s climate is hot and dry, which means a fire has the potential to spark anywhere when the conditions are right.
By growing fire-resistant plants, creating defensible zones, and building hardscapes, you can make a Firewise landscape that better protects your home from wildfires. Get your community involved, too–– the more homes with defensible spaces and fire-resistant landscapes, the slower the spread of wildfires.
Simple tasks can help make a safe landscape. Remember to:
- mow the grass
- water the plants
- prune shrubs and trees
- keep plants separated
- remove dead and unhealthy plant material
Need help designing a defensible space? Don’t know which fire-resistant plants to grow? Don’t have time to mow the lawn? Hire a Denver lawn care pro to help with your firescaping.