Fruit Trees for White Sulphur Springs and the Smith River Valley, Montana

On January 13, 2024, the NOAA station in White Sulphur Springs read −46°F, and the Deadman Creek station, in a creek bottom at the south foot of Kings Hill Pass, read −48°F. KRTV reported it may have been colder still at Newlan Creek, where the sensors stopped working at −50°F. In that same cold snap the Pickfoot Creek station, up in the Big Belts about 1,600 feet above town, bottomed out at −38°F. That spread is what fruit trees for White Sulphur Springs and the Smith River Valley come down to: cold settles on the floor and in the creek bottoms, and a little height with somewhere for it to drain off below you is worth real degrees.

This map covers the head of the Smith River Valley in Meagher County, west-central Montana: White Sulphur Springs, the floor down to Fort Logan, Springdale and Buckingham toward the Big Belts, Loweth under the Castle Mountains, and Newlan Creek and Lake Sutherlin at the foot of the Little Belts. Type your address in the box on the map to get the number for your own place, and the list of what we sell that has come through it.

How to read this map

The number at every spot is the 30-year planning low, the same number our cold hardiness calculator uses. It leans to the safe side on purpose, and it isn't the record. The MFTC zone puts it in half zones (−46°F is MFTC 2a, −44°F is 2b). "Typical winter" is an average year's coldest night, the kind of number USDA zones are built on, which is why the USDA map puts White Sulphur Springs in zone 4b and we put it in 2a. The spring layer shows how many degrees warmer or colder a spot runs than the middle of White Sulphur Springs on a still, clear night at bloom.

The middle of this map's growing ground plans for −46°F (MFTC 2a), and half of it falls between −47°F and −44°F. The warm end is the benches on the south and west sides: Loweth plans for −39°F (MFTC 3a), and the warmest twentieth of the ground runs −41°F or better. The cold end is the north side under the Little Belts, where Forest Green plans for −53°F (MFTC 1b) and the coldest twentieth runs −50°F or worse. White Sulphur Springs, the reference point, plans for −46°F (MFTC 2a), with a typical winter around −25°F.

Why the map looks the way it does

The Smith River Valley is a bowl ringed by the Big Belts on the west, the Little Belts on the north and the Castle Mountains to the southeast. On a clear, calm winter night the floor radiates its heat to the sky and makes most of its own cold, and cold off all three ranges slides down the creeks to join it. The only low way out is down the valley to the northwest: the floor drops from about 5,030 feet in town to about 4,900 feet where the North and South forks meet and 4,636 feet at Fort Logan, and below the mouths of Big Birch and Newlan creeks the river cuts through an igneous sill before dropping into Smith Canyon, about 1,000 feet deep. Cold air tends to back up above a narrows like that. The map reads the forks and Fort Logan at −48°F against −46°F in town.

Above the floor the air on a calm night is warmer. On January 5, 2004, the older White Sulphur Springs #2 station read −36°F and the Millegan station (4,970 feet, off the northwest corner of the map) −37°F, while Pickfoot Creek (6,650 feet) read −22°F and Spur Park (8,100 feet) −28°F. Over the 12 years both have on file, the #2 station's coldest night of the year ran a median 4°F colder than Spur Park's, 3,000 feet higher. That mild band on the slopes is the thermal belt, and the map picks it up on the benches 150 to 210 feet above the floor, which plan for −39°F to −44°F. A Hungarian study of 69 clear, calm nights found a valley floor averaged 6.7°F colder than a slope 230 feet higher.

The creek bottoms coming out of the mountains run colder than the floor. The Deadman Creek station sits at 6,450 feet in a bottom at the foot of Kings Hill Pass, and its coldest night of the year runs a median 10°F colder than Spur Park's, 3 miles away and 1,650 feet higher, and 10°F colder than the newer town station's. It gets 37 frost-free days a year to Spur Park's 75. Cold made on the high slopes drains into a bottom like that and sits. The map plans for −52°F there, 4°F colder than the −48°F the station has actually recorded. The whole north end shares some of it: creeks like Newlan and Sheep come down off the Little Belts there, and it's snow country (Showdown holds Montana's snowfall record, 33 feet in one winter), and snow makes the air above it colder.

Not every bad night sorts out by terrain. In the February 1989 outbreak Spur Park hit −51°F while the #2 station in town bottomed out at −43°F. When deep arctic air pours in over the whole region there's no warm layer for the benches to sit in, and higher can be colder. The planning low is built from records that hold both kinds of night; the spring layer is the calm-night pattern only, so in a windy spring freeze the warm benches won't be warm.

A few smaller things shape the floor. About two-thirds of the valley's irrigated ground is flood irrigated in late spring and early summer, and wet hay meadows are low and grassy (tall grass keeps the ground's stored heat from reaching the air), so they run cold on a frost night. Town heat is small; the map gives built-up ground no more than 2.5°F. Hot Springs Creek starts from 130°F springs in the middle of town, but nobody has measured what it does to the air. And the two NOAA stations in town, about a mile apart, don't agree: the newer one gets a median 119 frost-free days to the older #2 station's 83, and on December 7, 2013 it read −11°F while every other station around read −28°F to −36°F, yet it hit −46°F on January 13, 2024. We couldn't find where either one sat, but a small difference in position seems to count on some nights and not on the worst one.

White Sulphur Springs: Main Street, the Castle hill and the North Fork

Town sits on the floor at the foot of the Castle Mountains, with the North Fork of the Smith crossing its northwest side: the center sits at about 5,030 feet, only 60 feet above the lowest ground nearby, and plans for −46°F (MFTC 2a), typical winter −25°F. Within 3 miles the floor runs −47°F at the median, the benches −45°F, and the warmest tenth of the growing ground −44°F. Higher ground near town buys you about 2°F on the winter number and a lot more at bloom.

Doak Trailer Court, on a bench about 150 feet above the floor on the east side, plans for −44°F (MFTC 2b), typical winter −23°F, and runs 8°F warmer than the middle of town on a still spring night, the best spring reading of any named place on the map. Mikesell Trailer Court, down on the floor on the west side at 5,011 feet, plans for −46°F (MFTC 2a) and runs about 1°F warmer than the center at bloom. The Castle (the old Sherman house, now the Meagher County Museum) sits on a hilltop on the northeast side, and ground like that, up off the floor with room for cold to drain away below it, should read more like Doak. Type your address in and check.

The newer NOAA station hit −46°F on January 13, 2024, the same as the town's planning low, so the number isn't paranoid; it's a night this town has already had. Build a town lot around trees that have come through −50°F, like Kerr applecrab and Brookred plum. Trees rated −45°F, like Haralson, are worth a try 1°F short, on a higher lot with snow over the roots and a south or west wall. Early bloomers go on the east-side bench ground.

Down the valley: the forks, the hay meadows and Fort Logan

Below town the valley gets lower and flatter. Where the North and South forks meet, southwest of town, the floor sits at about 4,900 feet with no rise at all: −48°F (MFTC 2a), typical winter −26°F, and 3°F colder than town at bloom. Below the forks the river meanders through shallow lowlands and hayfields. Fort Logan, the lowest named place on the map at 4,636 feet and 10 feet above the floor, plans for −48°F (MFTC 2a), typical winter −27°F, and runs 2°F colder than town at bloom.

The low end has the harshest records in the valley. An old station 4 miles east-southeast of Fort Logan, at 4,710 feet, kept only nine winters (1894 to 1905), but it averaged a −37°F yearly low and hit −61°F on February 11, 1899. Another short-lived station 24 miles north-northwest of town, at 4,391 feet, averaged a −33°F yearly low from 1966 to 1982. The planning low only uses winters since 1995, but those old records point the same way the map does. Down here plant what has come through −50°F, like Mantet apple and Larinskaya pear, and keep apricots off this ground.

Springdale, Buckingham and the Big Belt foothills

West of town the ground climbs toward the Big Belts, the range between the Smith and the Missouri. The Springdale Hutterite Colony sits on a nearly flat bench at 5,260 feet, 160 feet above the floor: −44°F (MFTC 2b), typical winter −23°F, and 4°F warmer than town at bloom. Buckingham, farther west at 5,676 feet, sits on a hillside 170 feet above its floor at a 7.6 percent grade, right in the 4 to 8 percent range Montana State recommends: −42°F (MFTC 2b), typical winter −21°F, and 6°F warmer than town at bloom. On ground like that the cold keeps sliding past instead of settling. Up in the Big Belts, Pickfoot Creek averages a −20°F yearly low and gets 93 frost-free days, against −24°F and 83 days at the #2 station 1,600 feet below.

The trade-off out here is dryness and wind. The lowlands west and northwest of town get under 12 inches of precipitation a year, and open benches lose their snow to the wind, which leaves roots exposed. Hold snow with a windbreak of 30 to 40 percent density, but never run one across the slope below the trees, where it dams cold air back into them. These benches are where trees rated −45°F become good picks: Goodland apple, Toka plum and Evan's Bali tart cherry. At Buckingham, Meteor tart cherry (rated −40°F) is worth a try, 2°F short. If you're over the Big Belts on the Missouri side, the Townsend, Boulder and Broadwater Valley map covers you.

Loweth, Moss Agate and the Castle Mountains

The Castle Mountains are an island range southeast of town, topped by Elk Peak at 8,589 feet and named for the 50-foot rock spires on their western slopes. The Elk Peak station, at 7,600 feet, has a 30-year number of −40°F and an average winter low of −18°F over its 14 years on file, the mildest of any station in the valley. At the south edge of the map Loweth sits on a bench at 5,800 feet, 210 feet above its floor: −39°F (MFTC 3a), the warmest named place on the map, typical winter −21°F, and 3°F warmer than town at bloom. Don't read it as a different climate, though: Loweth's old NOAA co-op station (1927 to 1957) averaged a −30°F yearly low, about what the old town station averaged, and hit −43°F on February 8, 1936. Moss Agate, about 6 miles west at 5,239 feet, sits at the toe of the slope right at the edge of the pool: −46°F (MFTC 2a), typical −26°F, 1°F colder than town at bloom. The gap between its −46°F and Loweth's −39°F shows what a couple hundred feet above the pool can be worth here.

Up in the Castles, Castle Town (6,050 feet, on an 11 percent hillside 130 feet above its floor) plans for −42°F (MFTC 2b) and reads 7°F warmer than town at bloom; Robinson, at 6,736 feet on a 25 percent slope, plans for −41°F (MFTC 2b). The exception is Bruno, in a draw near the southeast corner at 5,509 feet: −42°F in winter, but 5°F colder than town on a spring night, the worst spring reading of any named place on the map. Draws carry cold down at night, so a draw can look fine in January and still lose the bloom.

At Loweth, trees rated −40°F clear the number, like Sweet Sixteen apple (in MSU's statewide trials), Pipestone plum and Luscious pear. The Castle Town slopes, with a 7°F spring edge, are where I'd try apricots: Westcot, Morden 604 and Debbie's Gold all clear −42°F. Keep them out of Bruno's draw.

Newlan Creek, Lake Sutherlin and the foot of the Little Belts

Newlan Creek Reservoir sits about 12 miles north of town at the foot of the Little Belts; the fishing access, on a toe slope at about 5,280 feet, plans for −47°F (MFTC 2a), typical winter −26°F, even with town at bloom. Lake Sutherlin, northeast of town at about 5,490 feet, sits in a bottom: −48°F (MFTC 2a), 2°F colder than town at bloom. Don't count on either reservoir to warm its shore; we couldn't find ice records for either one, and the map reads the ground along the water as cold as the floor.

Farther up it gets colder. Wolsey, at 5,946 feet on a 16 percent hillside, plans for −52°F (MFTC 1b), typical winter −30°F, though it reads 7°F warmer than town at bloom because the cold drains past it on a spring night. Forest Green, at 6,071 feet in a draw, plans for −53°F (MFTC 1b), typical −31°F, and 3°F colder at bloom, the coldest named place on the map. It's the same kind of ground as Deadman Creek, where the median last 32°F comes around June 30 and the first fall 32°F around August 5.

Up here the winter number rules out most tree fruit. Good picks are rated −55°F or colder: September Ruby apple, Rescue applecrab and Dolgo crabapple. Trees rated −50°F, like Chestnut applecrab and Honeyberry, are worth a try 2°F to 3°F short, on hillsides like Wolsey's rather than in the draws. Minnesota's best survivors of the 1996 winter (Rescue, Dolgo, Chestnut and Centennial) came from plots that saw −50°F to −55°F. With a frost-free season measured in weeks in the creek bottoms, bush fruit and crabs are the safest bets.

Spring frost and bloom in the Smith River Valley

NOAA station records for 1991 to 2020 put the median last 32°F at May 20 at the newer town station, the last 28°F around May 11 and the first fall 32°F around September 19, a 119-day frost-free season. The older #2 station ran later and shorter: last 32°F around June 8, last 28°F around May 21, first fall frost around September 5, 83 days. One year in ten the last 32°F comes after June 12 (newer station) or June 26 (older). At Deadman Creek, one year in ten, the last 32°F comes after July 16. PlantMaps' frost windows for town don't match the NOAA medians; go by the station records.

The 28°F date matters most, because open blossoms of apple, pear, cherry, peach, apricot and plum all start dying at about 28°F (Michigan State's Mark Longstroth). But only about 15 percent of apple blossoms need to set for a crop (Minnesota's fruit people), and most fruit can lose half its bloom with no real effect, since frost thins it for you; clustered fruit like cherries forgives less. Fully open haskap flowers take 19°F. Spring 2026 showed the bad case: Ed Schultz's farm at Gallatin Gateway hit 15°F during bloom and he got no fruit at all.

On the spring layer the benches and hillsides read best: Doak Trailer Court 8°F warmer than town, Castle Town and Wolsey 7°F, Buckingham 6°F, Springdale 4°F, Loweth and Robinson 3°F. The worst are Bruno's draw at 5°F colder, the forks and Forest Green at 3°F colder, and Fort Logan and Lake Sutherlin at 2°F colder. NC State's fruit guide says 3°F to 4°F can separate no crop from a full one, so an 11°F gap between the forks and the Doak bench on a still bloom night is huge.

Site comes first; the FAO's frost protection manual calls it "the single most important method of frost protection." Put apricots, plums and tart cherries on the highest bench or hillside ground you have, off the floor and off the windswept top, and put apples, honeyberries and currants lower. Bob Purvis, one of our grower friends, likes an east-facing slope, and a north slope holds apricots and plums back. Through bloom, mow under 2 inches, don't till, and water a day or two before a frost night. Frost cloth of 0.5, 0.9 and 1.5 ounces per square yard gains about 4°F, 6°F and 8°F (Alabama Extension's figures).

What the weather records say

The coldest readings on file in NOAA station records: −61°F near Fort Logan on February 11, 1899 (nine winters only); −51°F at Spur Park on February 2, 1989; −48°F at Deadman Creek and −46°F at the newer town station, both on January 13, 2024; −43°F at the #2 town station on February 4, 1989; and −42°F at the old town station (1895 to 1977) on January 27, 1916. Other big outbreaks hit in February 2014 (−36°F at #2) and December 2022 (−42°F at Millegan).

USDA's 2023 map, as PlantMaps shows it, puts White Sulphur Springs in zone 4b (−25°F to −20°F), up from 4a on the 2012 map. That's built on the average winter's coldest night, which fits the town stations' average yearly lows of −22°F and −24°F. We put town in MFTC 2a at −46°F because we plan for the bad night: NOAA station records show the worst night in about 30 winters runs a median 13°F below a station's average winter low, and here the newer station's −46°F came in 24°F below its average. Don't plant tenderer trees because of the move to 4b.

What you can grow here

We couldn't find a single commercial orchard, u-pick or cidery in Meagher County; this is ranch country, sheep in Charles Bair's day and hay and beef cattle now. MSU calls apples the most dependable fruit in Montana, then pears, and says Minnesota and Canadian cold-hardy apples suit most sites east of the Divide.

Benches and foothills that plan for −44°F or warmer

• The east-side bench, Springdale, Buckingham, Castle Town, Robinson and Loweth.
• Good picks, rated −45°F or colder: Goodland (one of the most successful apples in MSU's trials), Haralson and Honeycrisp apples; Vekovaya pear; Toka plum (one of MSU's two best plums); Evan's Bali tart cherry; Westcot apricot where the spring reading is best; and everything in the floor list.
• Worth a try at Robinson (−41°F), Buckingham and Castle Town (−42°F), and good picks at Loweth (−39°F): trees rated −40°F like Zestar!®, Meteor, Mount Royal and Ure.

Town and the valley floor, −45°F to −48°F

• Town, Mikesell Trailer Court, Moss Agate, the forks, Fort Logan, Newlan Creek and Lake Sutherlin.
• Good picks, rated −50°F or colder: Norda and Parkland apples; Kerr and Trailman applecrabs (if you only plant one tree, make it one of these) and Centennial, which Ed Schultz saw come through a −47°F winter with zero injury; Bolshaya pear; Brookgold and Northern Blue plums; Juliet dwarf cherry; Honeyberry, Montana Black Currant and Nanking Cherry.
• Worth a try on the higher lots, rated −45°F: Haralson, Honeycrisp, Goodland, Toka and Evan's Bali.

The north end and the cold draws, −49°F to −53°F

• Wolsey, Forest Green and the creek bottoms off the Little Belts.
• Good picks, rated −55°F or colder: September Ruby apple, Rescue and Trailman applecrabs, Dolgo, Trail and Siberian Crabapple.
• Worth a try, rated −50°F: Norda, Kerr, Centennial, Honeyberry, Montana Black Currant and Buffaloberry.

Rootstocks: MSU recommends standard rootstocks east of the Divide and says Bud and Budagovsky stocks are hardy enough for most of central and eastern Montana. At Ed Schultz's farm in Gallatin Gateway, Bud 118 has seen near −50°F under snow with no rootstock damage. Roots are the weak link (dormant apple roots are seriously injured near 10°F), so hold the snow, mulch, and keep the soil moist going into winter.

Water and season: drip is the only irrigation we advise for fruit trees in dry country, and if your trees sit in a flood-irrigated field, MSU says keep spring flooding to no more than three weeks of saturated soil. We taper water from mid-August so trees harden off before the first fall 32°F, which comes anywhere from early August to mid-September here. And with 83 to 119 frost-free days in town (the University of Vermont draws the short-season line at 135), late apples and pears may not ripen in the shorter spots. Plums and most pears set better with a second variety blooming alongside; our pollination maps show which ones pollenize which.

Local problems: MSU says fence at least 7 feet for deer, elk and moose. Voles work under the snow, the Meagher County Extension office ran a ground squirrel control workshop in 2023, and hail and wind are hard on young trees. On a sunny winter day the sunny side of a trunk commonly runs about 36°F warmer than the air, so paint trunks with white interior latex diluted 50 percent in late autumn, or use white guards.

Questions people ask

What hardiness zone is White Sulphur Springs, Montana?

USDA's 2023 map puts it in zone 4b (as PlantMaps shows it), based on an average winter's coldest night; ours is the bad night we plan for. Town plans for −46°F, MFTC 2a, and the newer NOAA station hit −46°F on January 13, 2024. Bench ground like Doak Trailer Court plans for −44°F (MFTC 2b).

When is the last frost in White Sulphur Springs?

NOAA station records for 1991 to 2020 put the median last 32°F at May 20 at the newer town station and June 8 at the older one, and one year in ten it comes after June 12 to June 26. The last 28°F, where open blossoms start dying, comes around May 11 to May 21.

Can you grow apples in White Sulphur Springs?

Yes, if you pick for −46°F. In town, plant apples that have come through −50°F, like Norda, Parkland or Kerr applecrab; Haralson, Honeycrisp and Goodland (rated −45°F) are worth a try on higher lots and good picks on benches that plan for −44°F or warmer.

What plums grow in central Montana?

In MSU's statewide trials Toka and Mount Royal did best. Here Toka (rated −45°F) is a good pick on benches that plan for −44°F or warmer, and Mount Royal (rated −40°F) fits only the warmest benches like Loweth. On the floor go with plums that have come through −50°F, like Brookgold, Brookred and Northern Blue.

Why is the Smith River Valley so cold?

It's a basin ringed by three ranges, with the only low exit down the valley to the northwest. On calm, clear nights the floor makes its own cold, cold air drains in off the mountains, and it pools. An old station near Fort Logan hit −61°F in 1899.

Do fruit trees need irrigation in the Smith River Valley?

Yes. Town averages about 13 inches of precipitation a year and the lowlands west and northwest of town under 12, below the 14 inches where MSU says irrigation is usually needed. Use drip, and taper the water from mid-August.

Warmer spots, colder spots

Here's the number to plan for at named places on the map, warmest first. Each one is the 1-in-30-year low for that spot: the cold hardiness calculator's number from the same weather stations, sharpened by our microclimate model for the ground right there. Zone is our MFTC zone, set by that one bad night, not by an average.

The weather stations behind it

These are the long-record stations in and around this map, with each one's own numbers since the winter of 1995-96. The last column is this map's 30-year number right at the station, which won't match the station exactly: it's a blend of the stations around it, the way the calculator works everywhere.

Source: NOAA records through ACIS, winters 1995-96 through 2025-26. What the "carried forward," "gaps filled" and AWOS rows mean is explained in how our microclimate maps work.