Replanting and Restoring a Yard After Wildfire in Montana

Should you replant right away after a fire?

Usually not everywhere. Montana DNRC's restoration page tells owners to get a qualified arborist for trees that threaten life or property, and that comes before any planting. Montana State University Extension's post on managing weeds after wildfire says monitoring helps decide whether natural recovery is likely or revegetation is needed, and notes that native vegetation may take several years to recover. Some of what looks dead in fall will come back in spring.

The exception is bare soil on a slope above the house, where erosion control can not wait. That is covered in erosion and flooding after a fire. Elsewhere, a season of watching usually saves money and plants.

What comes back on its own?

More than people expect. MSU Extension's MontGuide on fire-resistant plants notes that shrubs often survive fire by resprouting from their bases, and that succulent plants and plants full of water, as in spring, survive fire better than those with low moisture. It also says that while ground fires can girdle trees, new tissue laid down the following spring lets many damaged trees survive.

Trees need their own assessment, which is in which burned trees will live. For shrubs and perennials, the MontGuide's advice after a fire is to prune out dead branches and make sure the remaining plants are watered well. Wait for spring growth before pulling anything that might resprout.

Why do weeds come first?

Because burned ground is open ground. MSU's weed post explains that where burn severity and weed abundance were low, weeds may increase at first but are less likely to persist; where both were high, there may be fewer weeds at first but they are more likely to increase and persist. It warns that fall-germinating cheatgrass can colonize burned areas quickly where it was common before the fire, and that weed seed arrives in seed mixes and donated hay.

The same post makes two practical points: treating small infestations early is the most effective and least costly approach, and herbicide can work better than usual after fire because the plant litter that normally intercepts it has burned off. Our licensed weed control team handles this, and the cheatgrass guide explains why it matters for the next fire.

Does burned soil need fertilizer?

Usually not much. The MSU MontGuide explains that hot fires can lose as much as 70 percent of soil nitrogen and some other nutrients, but that nitrogen is often replaced quickly by soil microbes and nitrogen fixation, and nutrients released from burned organic matter can leave more available to plants than before the fire. It says there may be no reason to add large quantities of fertilizer.

What fire does take is soil organic matter, which the MontGuide says reduces the soil's ability to store water and encourages compaction and erosion. Mulch and compost, used in the right places, help more than fertilizer.

Should you test the soil before planting a garden?

If a building, vehicle or other structure burned nearby, yes. Oregon State University Extension's guidance on wildfire ash notes that burning buildings release different toxins than forests, and that contamination is more likely the closer a garden is to the fire. It recommends testing soil before replanting in spring: collect samples from several spots, label and map them, and ask a lab for a heavy metals analysis covering lead, cadmium, arsenic, nickel and mercury.

The same guidance says compost or clean bagged soil can help where ash was thick, though amendments are not necessary for most gardens, and that ash should never be cleaned up with a leaf blower. For yards that only saw smoke and light ash, see what wildfire smoke does to trees and gardens.

When is the best time to plant in western Montana?

For tree and shrub seedlings, early spring. The DNRC Montana Conservation Seedling Nursery's planting guide says the best time to plant in Montana is early spring, to take advantage of high soil moisture and cool temperatures, with an ideal planting temperature of 33 to 50 degrees. It says water is the greatest limiting factor to survival on most Montana planting sites and that reducing weeds and grasses around seedlings is extremely important.

The nursery, part of DNRC and based in Missoula, supplies locally adapted seedlings for conservation plantings, and DNRC's restoration page lists it alongside local conservation districts and DNRC service foresters for species choices. For yard trees, our tree planting guide covers the details.

Which plants are good choices for a rebuilt yard?

MSU Extension's MontGuide lists fire-resistant plants adapted to Montana. Among trees it lists quaking aspen, Rocky Mountain maple, birch and cherry. Among shrubs: chokecherry, red-osier dogwood, currant and gooseberry, mock orange, shrubby cinquefoil, skunkbush sumac, lilac, and most of the rose family. Among groundcovers and perennials: kinnikinnick, yarrow, blanket flower, flax, lupine, columbine, iris, creeping mahonia, stonecrops and daylilies, plus fescues and Kentucky bluegrass for turf.

The MontGuide explains that fire-resistant plants have supple, moist leaves and watery sap without a strong smell, and that most deciduous shrubs are fire resistant. It singles out junipers as highly flammable and says they should not be used as foundation plants in the wildland-urban interface. Any plant burns if it is dry enough. See fire-resistant plants for western Montana and junipers and other high-risk shrubs.

How should the new yard be laid out?

As defensible space from the start. The Insurance Institute for Business & Home Safety says clearing combustibles from the five feet around a home is the most effective defensible space action an owner can take, and the University of Nevada, Reno Extension's Wildfire Home Retrofit Guide suggests gravel, a concrete or brick walkway or other hardscape for that zone, including under attached decks. Rebuilding is the easiest time to get it right.

From five to 30 feet, the UNR guide describes a lean, clean and green zone: sparse plants grouped in separate islands, dead material removed, and plants kept green and irrigated through fire season. MSU's MontGuide suggests rock mulch where wildfire threatens, since embers can ignite bark mulch. Our guides to zone 0, mulch choices and patios and paths as firebreaks go further.

Should new beds be mulched?

Yes, with the right material in the right place. MSU's MontGuide recommends wood mulch around the base of plants to moderate soil temperature, and in the same breath warns that sparks and firebrands can ignite bark mulch near a home and suggests rock mulch where wildfire is a threat. The answer is to split the yard: rock, gravel or hardscape in the five feet next to the house and under decks, and organic mulch in beds farther out, kept in separate patches rather than one continuous strip.

Mulch also helps the soil problems fire leaves behind. The MontGuide notes that fire burns soil organic matter, which reduces water storage and encourages compaction and erosion, and Oregon State's ash guidance lists mulch and drip irrigation among the steps for gardens after fire. New plantings on burned ground dry out quickly, so mulch and water together give them the best start.

Does irrigation need rebuilding too?

Check it before you assume it works. If fire, heat or cleanup equipment reached any part of the yard, run every zone and look for broken heads, melted fittings and dry patches before replanting. The green zone only works if water reaches it, and new plantings are the most dependent on it: the DNRC nursery guide names water as the greatest limiting factor for seedling survival in Montana.

Our irrigation team repairs and redesigns systems, and our guide to lawns and irrigation as fire breaks explains how to plan the green band.

What about lawn on burned ground?

Lawn near the house can be a useful green break when it is irrigated and mowed, and MSU's list includes Kentucky bluegrass and fescues. On slopes and outlying ground, be careful with quick grass seeding: Oregon State University Extension's erosion guide calls seeding a marginal practice on forest sites and warns that non-native grasses can crowd out natives and increase fire risk.

For the lawn itself, see sod or seed and when to put in a new lawn.

Where we fit in

We help in the order that works: hazard trees and cleanup, weed control, soil and grading, then landscape design and installation built around defensible space, with irrigation that keeps it green. It is one part of recovery covered in our Montana Wildfire Guide, and the same layout is what our fire mitigation work maintains afterward. Call HJ Property Care & Tree Service at (406) 215-7319 or request a free estimate and we will walk the property with you.

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