The most flammable plants to keep away from your home are resinous evergreens (juniper, cedar and arborvitae hedges, cypress, spruce, pine, and fir), tall ornamental and dry grasses, and oily shrubs like sagebrush, rosemary, and broom. FireSmart BC says to keep the first 1.5 metres (5 feet) around your house free of all plants, and to keep conifers more than 10 metres (33 feet) away. In the US, NFPA Firewise USA and CAL FIRE use the same idea: a non-combustible first 5 feet, then lean, well-spaced plantings out to 30 feet.
Flammable plants tend to share a few traits. Many dry out fast or hold dead material inside their branches. Some shed dry leaves, needles, or stems that pile up at the base and make a layer of fine fuel. Dense, low foliage traps that debris and makes it hard to clean out. Many flammable species also make oils, waxes, or resins that catch fire easily and burn hot.
I garden in Armstrong, in the North Okanagan, which is wildfire country. This guide covers the 15 plants that fire agencies and extension researchers flag most often, the distances that matter, and what to plant instead.
Quick list: 15 flammable plants to avoid near your house
| Plant | Why it burns | Where it can go instead |
|---|---|---|
| Ornamental junipers (Juniperus spp.) | Volatile oils, dead needles trapped inside | Remove within 10 m (33 ft) |
| Cedar and arborvitae hedges (Thuja spp.) | Dense, resinous, holds dead foliage | Replace with a deciduous hedge |
| Leyland cypress (× Cuprocyparis leylandii) | Dense, fire-prone foliage | Replace near the house |
| Italian cypress (Cupressus sempervirens) | Resinous conifer | Replace near the house |
| Spruce, including dwarf Alberta and Colorado blue (Picea spp.) | Conifer needles and resin | Beyond 10 m (33 ft) |
| Pine, including mugo pine (Pinus spp.) | Resin, needle litter | Beyond 10 m (33 ft) |
| Fir (Abies spp.) | Resin, low branches | Beyond 10 m (33 ft) |
| Tall ornamental grasses (miscanthus and similar) | Tall, dry, fine fuel | Away from the house, isolated |
| Fountain and feather grasses | Fine, dry leaves | Away from the house, isolated |
| Cheatgrass (Bromus tectorum) | Dies and dries by early summer | Pull it everywhere |
| Big sagebrush (Artemisia tridentata) | Aromatic oils | Outer zone only |
| Rosemary (Salvia rosmarinus) | Aromatic oils, woody growth | A pot you can move |
| Scotch broom and other brooms (Cytisus spp.) | Listed as highly flammable | Remove |
| Eucalyptus (Eucalyptus spp.) | Oils, peeling bark, heavy litter | Remove near the house |
| Palms (especially untrimmed) | Dead fronds hang on the plant | Trim dead fronds or remove |
Sources for this list: FireSmart BC landscaping best practices, FireSmart BC Landscaping Hub, Oregon State University Extension PNW 590, UC Master Gardeners of Butte County, and Colorado State University Extension.
What makes a plant flammable?
No plant is fireproof. All plants burn when they get hot enough. But some plants catch fire faster and burn hotter than others.
FireSmart BC and Oregon State University Extension list the same warning signs. A plant is more flammable when it has:
- Leaves with a strong smell when you crush them
- Gummy, resinous sap with a strong odor
- Volatile waxes, terpenes, or oils in the leaves, twigs, and stems
- Fine, dry, or dead material inside the plant (twigs, needles, and leaves)
- Loose or papery bark
The dead material matters as much as the plant type. A healthy shrub with moist leaves can turn risky if dead stems build up inside it. FireSmart BC notes that even fire-resistant plants can become risky when they are neglected.
Home ignition zones: how far flammable plants should be from your house
FireSmart Canada calls the area within 30 metres (about 100 feet) of your home the home ignition zone. It splits that area into three parts. NFPA Firewise USA and CAL FIRE use close to the same distances in feet.
| Zone | FireSmart Canada and BC | NFPA Firewise USA | CAL FIRE | What to plant |
|---|---|---|---|---|
| Immediate | 0 to 1.5 m (0 to 5 ft) | 0 to 5 ft | Zone 0: 0 to 5 ft | No plants. Gravel, stone, pavers, or concrete. |
| Intermediate | 1.5 to 10 m (5 to 33 ft) | 5 to 30 ft | Zone 1: 5 to 30 ft | Fire-resistant plants, spaced in small groups. No conifers. No wood mulch. |
| Extended | 10 to 30 m (33 to 100 ft) | 30 to 100 ft (out to 200 ft) | Zone 2: 30 to 100 ft | Thin trees, prune low limbs, clean up dry grass and needles. |
Immediate zone: 0 to 1.5 metres (0 to 5 feet)
This is the most important zone. FireSmart Canada says to clear plants and combustible material down to mineral soil here, then cover it with gravel, brick, or concrete. Avoid woody shrubs and trees. This zone wraps around your house and anything attached to it, such as a deck.
FireSmart BC says even the most fire-resistant plant should be no closer than 1.5 m to a house or other structure. CAL FIRE says to use hardscape here with no combustible bark or mulch.
Intermediate zone: 1.5 to 10 metres (5 to 33 feet)
Here you can plant, but choose fire-resistant plants and non-combustible landscaping materials. FireSmart Canada says to keep woody debris (including mulch) out of this zone. FireSmart BC says coniferous trees should not be within 10 metres of your home.
The US guidelines add a few spacing numbers. NFPA suggests at least 18 feet between tree crowns in this zone and a mature canopy no closer than 10 feet to the house. Oregon State recommends 10 feet or more between groups of plants and at least 15 feet between tree branches and your home.
Extended zone: 10 to 30 metres (33 to 100 feet)
The goal here is to slow a fire, not to stop it. FireSmart Canada says to thin evergreens so there are at least 3 metres (10 feet) between tree crowns and to remove branches up to 2 metres (about 6.5 feet) from the ground. This is where conifers and grasses belong if you want to keep them.
The 15 most flammable plants to avoid near your home
1. Ornamental junipers
Junipers top almost every list. FireSmart BC calls cedars and junipers “extremely flammable” and says they often pose the most significant risk for home ignition. Oregon State Extension names spreading and upright juniper as a highly flammable shrub that is often planted around homes. Its photo of an improperly pruned juniper shows the dead, dry interior that makes it risky.
What to do: remove junipers from the first 10 metres (33 feet). If you keep one farther out, clean the dead material out of the center each year.
2. Cedar and arborvitae hedges
In BC, a “cedar hedge” is usually arborvitae (Thuja). FireSmart BC says cedars and junipers “have been used extensively to provide privacy. However, they are extremely flammable and often pose the most significant risk for ignition of homes and other structures.” Oregon State Extension shows an arborvitae with dry, dead material in its interior as an example of high fire risk.
Of the plants on this list, I tend to be asked most often about arborvitae. Its dense evergreen foliage, resin, and habit of trapping dry needles and debris in its branches and at its base make it more flammable than most landscape plants. To lower the risk from an existing hedge, remove dead inner branches and foliage, clear dry litter from the base, and trim the lower limbs up off the ground. Avoid planting new Thuja near buildings in fire-prone areas. (If you are still deciding on a hedge, my guide to Emerald Green arborvitae spacing covers the plant itself, but keep it well away from the house.)
3. Leyland cypress
Oregon State Extension points to Leyland cypress as a fire-prone plant. In the 2010 Oak Knoll Fire in Ashland, Oregon, a border of Leyland cypress was completely consumed. Wood shake roofs, high grass, and fire-prone plants like Leyland cypress all contributed to home losses in that fire.
4. Italian cypress
The tall, narrow columns of Italian cypress are a classic look in warm climates. UC Master Gardeners list Italian cypress with the other flammable conifers. Rows of any dense conifer give fire a continuous path to follow.
5. Spruce (including dwarf Alberta and Colorado blue spruce)
FireSmart BC names spruce among the coniferous trees that “are highly flammable and should not be within 10 metres of your home.” Dwarf Alberta spruce and blue spruce are common foundation plants in cold climates. Check the inside of any spruce near your house for dead needles.
6. Pine (including mugo pine)
Pines carry resin and drop a steady layer of needles. FireSmart BC lists pine with the conifers to keep beyond 10 metres. Pine needles also land on roofs and in gutters, where embers can catch them.
One note: Oregon State says ponderosa pine and western larch are among the most fire-resistant conifers because of their thick bark and moist foliage. That is about how well a mature tree survives a fire. It does not make a pine a good plant beside your house.
7. Fir
FireSmart BC includes fir in its list of conifers to keep away from the home. FireSmart BC lists low tree branches as ladder fuels and says to prune all branches within 2 metres (6.5 feet) of the ground. If you have a large fir that you cannot remove, prune the lower branches and rake up needles and cones.
8. Tall ornamental grasses
Oregon State Extension leaves ornamental grasses off its fire-resistant list because most grow too tall, and tall grasses beneath trees can spread fire into the branches. FireSmart BC lists ornamental grasses among common ladder fuels.
What to do: plant grasses in isolated spots away from the house, not under trees. Cut back dry, dead stalks.
9. Fountain and feather grasses
UC Master Gardeners name feather and fountain grasses as flammable plants to avoid in a firewise landscape. Their fine leaves dry fast. Treat them like other ornamental grasses and keep them out of the zones closest to the house.
10. Cheatgrass and other dry annual grasses
Cheatgrass (downy brome) is a weedy annual grass. Colorado State University Extension says it turns brown and dies by early summer, leaving thick, continuous dry fuel. A cheatgrass fire on flat ground with a 20 mph (32 km/h) wind can make flames up to 8 feet (2.4 m) tall and move more than 4 mph (6.4 km/h). The same fact sheet says to clear cheatgrass from the 30 feet around your home.
Pull it in spring or fall before it sets seed. Seeds can last in the soil for four or five years, so plan on follow-up weeding.
11. Big sagebrush
Big sagebrush grows wild in dry grasslands in the West. UC Master Gardeners list sagebrush as a flammable plant. Its silvery leaves smell strong when crushed, which is one of the warning signs. Leave it in wild areas well away from buildings.
12. Rosemary
Rosemary surprises people because it is a kitchen herb. UC Master Gardeners list it as flammable. Its leaves are full of aromatic oils, and older plants get woody. In cold zones, many gardeners grow rosemary in a pot (see my guide on how to grow rosemary). A pot is easy to keep off the deck and out of the first 1.5 metres in summer.
13. Scotch broom and other brooms
UC Master Gardeners include broom on their list of flammable plants to avoid or remove.
14. Eucalyptus
This one matters for readers in warm-winter areas. UC Master Gardeners list eucalyptus as flammable and suggest removing it from a firewise landscape. Keep the ground under any eucalyptus clear of fallen leaves and bark, and keep it well away from buildings.
15. Palms (especially untrimmed)
UC Master Gardeners also list palms. The risk comes from dead fronds that hang on the trunk and stay dry. If you have palms near your house, trim off dead fronds every year.
Is lavender flammable?
Lavender is aromatic, so it often shows up on flammable plant lists. But UC Master Gardeners list lavender among their fire-resistant flowering plants, and they call salvias an exception to the aromatic sap rule. The safe approach is the same for any plant: keep lavender out of the first 1.5 metres (5 feet), water it, and cut out dead stems.
Traits of fire-resistant plants
FireSmart BC and Oregon State describe fire-resistant plants this way:
- Moist, supple leaves (often wide and flat)
- Water-like sap with little or no smell
- Open, loose branching
- Little dead wood, and little build-up of dry material
Oregon State says most healthy deciduous shrubs and trees are fire-resistant. Fire-resistant plants can still burn, but they tend to produce fewer embers.
What to plant instead of cedars and junipers
FireSmart BC publishes a list of lower-risk plants for hedges, privacy, and screening. Here are picks from that list that suit cold-winter gardens like mine. Check hardiness for your own zone before you buy.
| Need | Instead of | Try (from the FireSmart BC hedge list) | Approx. height and width |
|---|---|---|---|
| Tall, narrow screen | Pyramidal cedar | Swedish columnar aspen (Populus tremula ‘Erecta’) | 12 m tall, 1.5 m wide |
| Narrow flowering tree | Italian cypress | ‘Emerald Spire’ flowering crabapple (Malus ‘Emerald Spire’) | 4.5 m tall, 1.8 m wide |
| Narrow shrub hedge | Upright juniper | ‘Standing Ovation’ saskatoon (Amelanchier alnifolia ‘Obelisk’) | 3.5 m tall, 0.8 m wide |
| Slim clipped hedge | Cedar hedge | ‘Straight Talk’ privet (Ligustrum vulgare ‘Swift’) | 3.5 m tall, 0.6 m wide |
| Medium shrub screen | Spreading juniper | Ninebark (Physocarpus opulifolius) | 1.8 m tall and wide |
| Larger shrub screen | Arborvitae | Common lilac (Syringa vulgaris) | 3.6 m tall, 2.7 m wide |
| Winter color | Blue spruce | Red twig dogwood (Cornus sericea) | 2.4 m tall, 3 m wide |
| Tough windbreak | Mugo pine | Siberian peashrub (Caragana arborescens) | 4.5 m tall, 3 m wide |
| Low evergreen | Low juniper | Boxwood (Buxus) | Varies by type |
There are no conifers on the FireSmart BC hedge list. For year-round green, it suggests broadleaf evergreens. In mild coastal gardens, that list includes strawberry tree (Arbutus unedo), Portuguese laurel (Prunus lusitanica), and Japanese pieris (Pieris japonica).
For low plants near the house (but still outside the 1.5 m zone), see my list of ground cover plants. UC Master Gardeners name creeping thyme, creeping phlox, sedums, and hens and chicks as fire-resistant ground covers. FireSmart BC calls low ground covers “living mulch.”
Landscaping mistakes to avoid next to a house
Planting flammable plants near windows and other weak spots is one of the riskiest choices in a wildfire area. These are the situations to avoid, especially in the first 1.5 metres (5 feet):
- Planting flammable species under windows. Juniper, cedar, or rosemary under a window can catch embers and put flames and heat right against the glass.
- Placing dense shrubs under vents or eaves. Shrubs like arborvitae or cypress below soffit vents can carry flames and embers up toward the roof. NFPA suggests 1/8 inch (3 mm) metal mesh over vents.
- Using bark mulch or pine needles against the foundation. FireSmart BC says bark, evergreen needles, and other plant-based mulches should not be used next to buildings. Use gravel or rock instead. Oregon State also warns against recycled rubber mulch, which is highly flammable.
- Letting ornamental grasses dry out against the house. Dry grass stems are fine fuel and a ladder for flames.
- Running tall hedges into wooden fences or decks. FireSmart BC warns that a hedge can become a path for fire to reach a fence or building.
- Letting dead plant debris pile up. Dead leaves, twigs, and needles around foundation plantings or in gutters can catch embers. FireSmart BC says 50% of home ignitions caused by wildfires are started by embers.
- Planting under or into the roofline. FireSmart BC says to keep branches out from under rooflines. CAL FIRE says to remove branches within 10 feet (3 m) of a chimney.
- Blocking hose bibs or access paths with plants. This makes it harder for you or firefighters to reach water and defend the house.
How to make an existing yard safer, step by step
- Start at the house. Clean roofs and gutters of leaves and needles.
- Clear the first 1.5 metres (5 feet). Remove plants and bark mulch. Lay gravel, stone, or pavers.
- Remove or move junipers, cedars, and other conifers within 10 metres (33 feet). Start with any that touch the house or sit under windows.
- Prune tree branches up to 2 metres (6.5 feet) from the ground. NFPA suggests 6 to 10 feet, and no more than one third of the height on short trees.
- Mow grass to 10 cm (4 inches) or less. FireSmart BC says grass under 10 cm is less likely to burn intensely. Do not scalp it shorter, since it dries out faster.
- Water your lawn and beds. FireSmart BC says a healthy lawn needs about 2.5 cm (1 inch) of water once or twice a week. Follow local watering restrictions.
- Space shrubs apart. CAL FIRE says on flat ground, leave two times the shrub’s height between shrubs (four times on moderate slopes, six times on steep ones).
- Repeat the cleanup every year, as plants grow and debris builds up.
Cold-climate and Okanagan notes
In the BC Interior and other zone 3 to 6 areas, many of the evergreens sold for winter green are on this list: cedar hedges, junipers, mugo pines, and spruce. The swap table above has hardy deciduous options for each one.
Prune conifers in early to midwinter, as Oregon State suggests, to avoid attracting insect pests.
FireSmart BC has a free fire-resistant plant tool that lets you pick your region, and a Plant Program that tags lower-risk plants at participating garden centres.
FAQ
What are the most flammable landscape plants?
Junipers and cedars top the list. FireSmart BC says “they are extremely flammable and often pose the most significant risk for ignition of homes and other structures.” Other conifers, tall and dry grasses, sagebrush, rosemary, broom, eucalyptus, and untrimmed palms are also high risk.
How close to my house can I plant shrubs?
No closer than 1.5 metres (5 feet), even for fire-resistant plants. That rule comes from FireSmart BC. NFPA and CAL FIRE also call the first 5 feet a non-combustible zone.
Are cedar hedges a fire hazard?
Yes. FireSmart BC rates cedars and junipers as the plants that “often pose the most significant risk for ignition of homes and other structures.” If you keep a cedar hedge, clean out dead foliage, clear litter from the base, and keep it away from the house, fences, and decks.
Do I have to remove all my evergreens?
Not always. FireSmart BC says to remove anything combustible from the 1.5 metre zone and to look closely at conifers within 10 metres. Tall conifers farther out can stay if you prune lower branches and rake up needles and cones.
Are ornamental grasses a fire risk?
Yes, when they are tall and dry. Oregon State leaves them off its fire-resistant list. If you grow them, place them in isolated spots away from the house and trees, and cut back dead stalks.
Is bark mulch flammable?
Yes. FireSmart BC says bark, evergreen needles, and other plant-based mulches should not be used next to buildings. Use gravel or rock within 1.5 metres (5 feet) of the house.
Are fire-resistant plants fireproof?
No. All plants burn with enough heat. Fire-resistant plants ignite less easily and tend to produce fewer embers, as long as you water them and remove dead material.
What is the best fire-resistant hedge for privacy?
In cold climates, FireSmart BC’s hedge list includes Swedish columnar aspen, ‘Emerald Spire’ crabapple, ‘Standing Ovation’ saskatoon, ‘Straight Talk’ privet, lilac, and ninebark. In mild climates, broadleaf evergreens like Portuguese laurel and strawberry tree give year-round screening.
Where to start this weekend
Walk around your house and look at the first 1.5 metres (5 feet). Pull out anything dry, any bark mulch, and any juniper or cedar touching the walls. Then work outward to 10 metres (33 feet). Small steps close to the house count the most.
Seed companies I like
These are the seed companies I order from for my own garden.
- Botanical Interests: beautiful packets with growing notes printed inside
- High Mowing Organic Seeds: certified organic, grown in Vermont
- True Leaf Market: big selection of hybrids, microgreens, and cover crops
Some links earn me a commission at no cost to you. As an Amazon Associate I earn from qualifying purchases.
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