Shown in photo: juniper
Commonly used landscape plants that pose a fire risk
In the age of wildfires that are more frequent and bigger and more difficult to control, the plants you choose for your landscape might also be selected with an eye toward safety.
Knowing which plants are highly-flammable will help you to create a fire-wise landscape to help protect your property.
In Colorado, some landscape plants can contribute significantly to wildfire risk, particularly when they are dry, resinous, densely planted, or connected to the home by other vegetation.
Importantly, there are no completely fireproof plants; CSU Extension emphasizes that plant selection, spacing, moisture, and maintenance all matter.
Plants to Be Especially Careful With These Plants
Junipers are among the biggest concerns. Their evergreen foliage contains volatile oils and can become highly flammable, particularly when dry. CSU recommends avoiding new evergreen plantings in the 5–30-foot zone around structures.
Pines, firs, and spruces can also present substantial fire risk because of their resin, needles, and evergreen structure. Existing trees should be carefully maintained, with attention to canopy spacing and removal of ladder fuels.
Gambel oak, three-leaf sumac, and mountain mahogany are common Colorado shrubs that CSU identifies as relatively flammable. This doesn't mean they should automatically be removed from every property, but they should be carefully managed especially close to structures.
Ornamental and native grasses deserve special attention. Once grasses turn brown and dry, they become fine fuels that can ignite easily and carry fire rapidly. This is particularly important on Colorado's Front Range during the Fall-through-Spring grass-fire season.
The Bigger Issue: Fuel Continuity
A single flammable plant isn't necessarily the problem. A continuous pathway of vegetation is. A dry shrub beneath a tree, connected to ornamental grasses and then to a wooden fence or house, can create what firefighters call ladder fuels and allow fire to move toward a structure.
CSU recommends breaking vegetation into separated islands and incorporating rock, gravel, patios, walls, and other noncombustible features.
Better Choices Near the Home
For the first 30 feet around a home, CSU Extension recommends selecting plants with low-flammability ratings, particularly those rated 8, 9, or 10 on its scale. Examples include Rocky Mountain penstemon, yarrow, prickly pear, cholla, snowberry, serviceberry, crabapple, and certain yuccas.
For a Colorado luxury landscape, the goal isn't to eliminate beautiful vegetation, it's to design strategically. Use low-flammability plants near the house, create breaks between plant groupings, keep vegetation healthy and adequately hydrated, remove dead material, and maintain appropriate tree spacing.
One important distinction: drought-tolerant does not automatically mean fire-resistant. Some drought-adapted evergreens contain oils or resins that make them highly combustible even when relatively healthy.
Knowing which plants are highly-flammable will help you to create a fire-wise landscape to help protect your property.
In Colorado, some landscape plants can contribute significantly to wildfire risk, particularly when they are dry, resinous, densely planted, or connected to the home by other vegetation.
Importantly, there are no completely fireproof plants; CSU Extension emphasizes that plant selection, spacing, moisture, and maintenance all matter.
Plants to Be Especially Careful With These Plants
Junipers are among the biggest concerns. Their evergreen foliage contains volatile oils and can become highly flammable, particularly when dry. CSU recommends avoiding new evergreen plantings in the 5–30-foot zone around structures.
Pines, firs, and spruces can also present substantial fire risk because of their resin, needles, and evergreen structure. Existing trees should be carefully maintained, with attention to canopy spacing and removal of ladder fuels.
Gambel oak, three-leaf sumac, and mountain mahogany are common Colorado shrubs that CSU identifies as relatively flammable. This doesn't mean they should automatically be removed from every property, but they should be carefully managed especially close to structures.
Ornamental and native grasses deserve special attention. Once grasses turn brown and dry, they become fine fuels that can ignite easily and carry fire rapidly. This is particularly important on Colorado's Front Range during the Fall-through-Spring grass-fire season.
The Bigger Issue: Fuel Continuity
A single flammable plant isn't necessarily the problem. A continuous pathway of vegetation is. A dry shrub beneath a tree, connected to ornamental grasses and then to a wooden fence or house, can create what firefighters call ladder fuels and allow fire to move toward a structure.
CSU recommends breaking vegetation into separated islands and incorporating rock, gravel, patios, walls, and other noncombustible features.
Better Choices Near the Home
For the first 30 feet around a home, CSU Extension recommends selecting plants with low-flammability ratings, particularly those rated 8, 9, or 10 on its scale. Examples include Rocky Mountain penstemon, yarrow, prickly pear, cholla, snowberry, serviceberry, crabapple, and certain yuccas.
For a Colorado luxury landscape, the goal isn't to eliminate beautiful vegetation, it's to design strategically. Use low-flammability plants near the house, create breaks between plant groupings, keep vegetation healthy and adequately hydrated, remove dead material, and maintain appropriate tree spacing.
One important distinction: drought-tolerant does not automatically mean fire-resistant. Some drought-adapted evergreens contain oils or resins that make them highly combustible even when relatively healthy.
If you're designing for wildfire resilience, the Colorado State University Extension/Colorado State Forest Service Firewise plant list is an excellent starting point. Here is CSU's Firewise Plant Materials guide.