Firewise Landscaping for Park City: What to Plant and What to Pull Out

The question nobody answers after the crew leaves

We do a lot of mitigation work on Park City properties. The crew thins the stand, takes out the dead conifers, pulls the junipers off the foundation, chips the slash, and the property is measurably safer than it was that morning.

And then the homeowner stands in the newly open space and asks the reasonable follow-up question: so what do I put back?

That question gets answered badly most of the time. The two common answers are both wrong. One is “nothing — bare ground is safest,” which produces an eroding, ugly, legally non-compliant lot that the owner comes to resent. The other is a nursery run that fills the space with whatever looked good on the lot, which on the Wasatch Back frequently means planting the exact species a mitigation crew just removed.

There is a real answer, and in Utah it is unusually well documented. Utah State University Extension publishes Firewise Plants for Utah Landscapes, compiled by the state Extension forester, and it is the closest thing to an authoritative species list for this climate. This guide works from it, adds the Park City code and elevation realities it does not cover, and is honest about the places the sources disagree.

Start here, because it reframes everything: no plant is fireproof

USU states this plainly and it deserves to be the first thing you read. No plant is fireproof. All of them will burn in a sufficiently intense fire. Firewise plants reduce risk; they do not eliminate it, and using them alone does not make a property safe.

A second point from the same source matters just as much: all trees add substantial fuel. There is no tree you can plant that adds no fuel load. Which means the decisions that actually determine your outcome are placement and maintenance— where the plant sits relative to your structure, and whether anybody keeps the dead material out of it. Species selection is the third-most-important variable, not the first.

That is genuinely good news, because placement and maintenance are both entirely within your control and neither requires buying anything.

What actually makes a plant firewise

It is not a mystical property of certain species. Firewise plants share one or more measurable traits:

• Higher tissue moisture, particularly during fire season, which is when it counts.
• Few volatile oils or flammable compounds.This is the single biggest strike against juniper and the aromatic evergreens — the chemistry is working against you.
• Less fuel overall, either because the plant is small or because it does not accumulate litter.
• A compact or low growth habit that interrupts a fire path rather than carrying it upward into a canopy.

From those traits comes the most useful single generalization USU offers: broadleaf trees are generally less flammable than conifers— pines, firs, spruces, and junipers. On a Wasatch property dominated by conifer, deliberately adding broadleaf diversity is a defensible-space improvement and a bark beetle resilience improvement at the same time.

The zone that is not a planting zone

Before any species list, the zones. These drive the decision far more than the plant tag does.

Zero to five feet — the non-combustible band

This is the strictest zone and the one homeowners resist most, because it is the strip you see from inside the house. The guidance is consistent across fire agencies: this band should have very low potential for ignition from flying embers, which in practice means non-combustible ground cover — rock, stone, gravel, or pavers.

Two specific things to get out of this band:

• Bark mulch. It is combustible, it holds embers, and it sits directly against your siding. Use gravel or stone here instead. Save the bark mulch for trees out in the yard, where it does real good for root zones.
• Woody evergreen shrubs. The juniper under the window is the textbook ignition path into a structure.

You can still have plants near the house — low, well-watered, herbaceous, widely spaced, in containers you can move. What you cannot have is a continuous combustible bed touching the building.

Five to thirty feet — the intermediate zone

Fire-resistant plants, non-combustible landscape features, and deliberate breaks in vegetation so there is no continuous fuel bed running at the house. This is where most of your actual planting design happens.

Remember that the ten-foot crown-separation rule applies to what you plant, not just to what you remove. A row of saplings installed four feet apart is a future code problem you are paying to create. Plant for the mature crown, not the nursery pot.

Thirty to one hundred feet — the extended zone

Managed native vegetation, broken-up brush, thinned understory. On steeper ground, more clearance is needed rather than less — fire moves uphill efficiently, and guidance for slopes runs to the full hundred feet. Our fire mitigation guide covers the zone work in detail, and the HB 48 and WUI code guide covers what is actually required of you now.

What to take out

Honest and short. These are repeatedly flagged by extension services and fire agencies as highly flammable, and near a structure they are a liability regardless of how good they look:

• Juniper— the most common and most consequential problem plant in Utah landscapes. High volatile oil content; burns hot, fast, and with intense radiant heat.
• Arborvitae— frequently planted as a privacy hedge, which means it is usually in exactly the wrong place. Also among the worst snow-load failures in this climate, so it fails twice.
• Yew and Leyland cypress.
• Sagebrush near structures.
• Conifers generally, within the first thirty feet.

General guidance is to remove highly flammable plants within thirty feet of the home, and farther out on steeper slopes.

A note on who to believe about juniper

Worth flagging because you will run into it. At least one Utah landscaping company publishes a blog post describing Rocky Mountain juniper as fire-resistant on the grounds that its dense foliage resists ignition when properly maintained. That directly contradicts USU Extension and fire-agency guidance.

When a vendor blog and a state extension service disagree about whether the thing the vendor sells is dangerous, follow the extension service. We are a vendor too, which is exactly why we are pointing at USU’s publication rather than asking you to take our word for it.

What to plant

Drawn from USU’s Utah list. Confirm cold hardiness against your own elevation before buying — most of these suit USDA zones 4 and 5, which covers the Wasatch Back, but a Heber valley-floor lot at 5,600 feet and an Empire Pass lot at 8,700 feet are not the same planting environment. Our Utah tree species field guide breaks down what already grows at each elevation band.

Trees

All trees add fuel, so these need placement and upkeep. Most want supplemental moisture here.

• Maple— and bigtooth maple is the species behind the Wasatch’s red fall color, so this is a native-ish win.
• Birch— choose borer-resistant selections, which matters a great deal in this region.
• Quaking aspen— best as young clumps, and not in valley bottoms. Worth reading our Sudden Aspen Decline guide before committing to aspen as a replacement planting, because the regional disease pressure is real.
• Poplar and cottonwood— need genuine space. Do not plant these near a driveway you care about.
• Willow— disease-prone as a tree; some shrub willows are good choices.
• California redbud— small, drought and heat tolerant.

Shrubs and woody vines

Low, spreading, or evergreen options:

• Kinnikinnick (bearberry), creeping Oregon grape, Bearberry and Rockspray cotoneaster, New Jersey tea, ceanothus, dwarf and large periwinkles.

Drought-tolerant options:

• Saltbush, western sandcherry, skunkbush sumac, russet buffaloberry, rugosa rose.

Usable, but only with active pruning:

• English ivy and Virginia creeper — control the spread. Firethorn (pyracantha) — low selections only. Honeysuckle — low-growing species only. Lilac needs irrigation here.

Perennials and groundcovers

This is the most productive category for the five-to-thirty-foot zone, because low herbaceous plants give you a real landscape without building a fuel ladder.

• Low / groundcover:hardy ice plant, snow-in-summer, sedums, hens and chicks, lamb’s ear, creeping cinquefoils, dwarf mouse-ear coreopsis, hardy geranium, evergreen candytuft.
• Drought-tolerant: yucca, fernleaf and silvery yarrow, penstemon (needs well-drained soil), lavender (cut it back regularly), flax, lily-turf, Russian sage.
• Moisture-loving: columbine, coral bells, iris, bergenia, pinks, fleabane, red valerian.
• Also good: blanketflower, Shasta daisy, sea thrift (dry, infertile sites), beach wormwood (very well-drained soil only).

Grasses

• Lower fuel load: crested wheatgrass (its growth form resists fire spread), buffalograss, western wheatgrass, Sandberg bluegrass, blue fescue.
• Only firewise if maintained: orchardgrass, ryegrass, and Kentucky bluegrass need mowing or grazing to stay firewise, and bluegrass needs irrigation on top of that. An unmowed, unwatered lawn going into August is a fuel bed, not a lawn.

Where the sources disagree, and what we do about it

Being straight about this is more useful than pretending the literature is unanimous.

Bitterbrushappears on USU’s firewise list as a drought-tolerant shrub. It also appears on at least one regional fire-agency list of highly flammable plants. Both are defensible — flammability depends heavily on moisture, age, and how much dead material has accumulated inside the plant.

Our working rule when sources conflict: default conservative inside thirty feet of a structure, and allow the more generous reading farther out. A species with a split reputation is fine at the back of a five-acre lot and not fine under a bedroom window.

One more honest caveat: USU’s publication has been in circulation for a while, and specific recommendations do get revised. Check the current version rather than a summary of it — including this one.

The mistakes we see most

Overwatering a firewise plant into a hazard

Counterintuitive and straight from USU: overwatering makes some plants grow too fast and become hazardous. Rapid soft growth plus accumulating dead interior material turns a low compact shrub into a fuel pocket. The plant did not stop being firewise; the maintenance did.

Assuming a relative is also firewise

USU warns against this specifically. Do not assume a plant is firewise because it is related to something on the list or has a similar common name. Common names in the nursery trade are unreliable and the genus is not the unit of flammability.

Planting something you are not allowed to plant

Several plants carry weediness or noxious-weed restrictions in Utah — sulfur cinquefoil, Mediterranean sage, annual kochia (use immigrant forage kochia instead), and some lupines, which are poisonous to livestock. Some yarrows and artemisias are volatile enough to use cautiously. Check with your county Extension office or the Utah Department of Agriculture before planting at scale.

Designing for the pot instead of the mature plant

The most common and most expensive error. Crown spacing, mature height, and distance from the structure all have to be designed for year fifteen. Mitigation you pay for twice is mitigation you designed once, badly.

Park City has rules about replanting, too

This surprises people. If your removal happened as part of a permitted project, replanting may not be optional.

Park City’s Land Management Code defines Significant Vegetation— in the residential districts, large trees of six inches in diameter or greater measured four and a half feet above the ground, plus groves of smaller trees and clumps of oak or maple covering fifty square feet or more at the drip line. Where Significant Vegetation is removed, code and plat notes have required that it be replaced in kind, with architectural guidelines allowing an alternative of multiple trees whose combined caliper is equivalent to what came out. In the residential zones the Planning Director determines Limits of Disturbance and may require mitigation for loss of Significant Vegetation.

And here is the provision that resolves a tension a lot of owners run into: a 2023 ordinance establishes that Significant Vegetation preservation is prioritized, but that Significant Vegetation may be removed or replaced where applicable to comply with Firewise Landscaping and/or Defensible Space regulations.

That matters. If you have been told a tree is protected and also told it has to go for defensible space, the code anticipates exactly that conflict and does not leave you stuck. Bring the specific requirement to Planning in writing rather than guessing.

If your removal is happening as part of a build or a remodel rather than as standalone mitigation, the Limits of Disturbance rules are the bigger story and they come with a posted security. Our guide to tree protection during construction covers that side, including how the protected root zone is actually calculated.

Park City also publishes a voluntary WUI approved-plantings list alongside its WUI Code resources. If your project is going through permit review, start from that list rather than from a nursery recommendation. Code chapters and thresholds have been amended repeatedly in recent years, so confirm current language with Park City Planning or in the municipal code before relying on any figure here.

Maintenance is the whole thing

If you take one item from this article, take this one. A firewise plant list buys you a modest advantage. Maintenance buys you most of the actual risk reduction, and USU’s own maintenance list is short enough to act on:

• Remove dead leaves and stems from the plants and from the ground. Dead material inside an otherwise green shrub is the fuel that matters.
• Prune trees to keep crowns thin and high. This is the same ladder-fuel logic as the rest of defensible space, applied to your ornamentals. See our pruning service— and note that the right window for most structural pruning in Utah is late winter, not fall.
• Remove individual plants to break up fuel continuity. Gaps are a design feature, not a failure.
• Thin and prune native vegetation near the house. The native stand is still fuel.

Do this annually and a mediocre plant list outperforms a perfect one that nobody touches.

Where Canyon Cutters fits

We are a tree and land-management outfit rather than a nursery, and the honest division of labor is this: we handle the removal, the thinning, the ladder-fuel work, the on-site chipping, and the structural pruning that keeps your plantings from becoming a problem. For larger acreage our land management program sequences that work across seasons, and where removal has opened unstable ground our erosion and drainage work keeps the soil where it belongs while new plantings establish.

What we will also do is tell you honestly which of your existing plantings are working against you, and which ones you have been told to remove that could stay. If you want the property walked with that specific question in mind, reach out through our contact page or call (201) 960-8275. The first visit is free and the assessment comes in writing.

This article summarizes publicly available guidance, principally from USU Extension, and is not a substitute for current code or for site-specific professional advice. Plant hardiness, flammability ratings, noxious-weed restrictions, and Park City code thresholds all change — verify species choices with your county Extension office and verify any permit-related planting requirement with Park City Planning before you buy or plant.