Fruit Trees for Mankato, North Mankato, St. Peter and New Ulm, Minnesota

In the January 1972 cold snap, NOAA's St. Peter station, on the floor of the Minnesota River valley at 795 feet, bottomed out at −38°F. The St. James station, up on the prairie at 1,070 feet at the edge of this map, got down to −27°F. That 11°F gap is the first thing to know about fruit trees for Mankato, North Mankato, St. Peter and New Ulm: this is a deep valley cut into flat farm country, and on a still, clear night the prairie's cold runs down into it and sits.

The map covers the Greater Mankato Area and the Minnesota River Valley from New Ulm down past St. Peter, across Blue Earth, Nicollet and Brown counties: Mankato, North Mankato, Skyline, Eagle Lake, New Ulm, Courtland, Hanska, St. Peter, Kasota, Lake Crystal, Madelia, Nicollet, Rapidan, Good Thunder and St. Clair. 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 big number is the 30-year planning low, the number our cold hardiness calculator uses (NOAA station records since the 1995-96 winter) with a small nudge for the ground around you. It's a safe number to plan around, not the record and not a promise of how often it comes. The MFTC zone is that number in half zones, the typical winter is an average year's coldest night (the kind of number USDA's map is built on), and the spring layer shows how much warmer or colder a spot runs than Mankato on a still, clear bloom night.

Mankato, the reference town, plans for −34°F, MFTC zone 3b, with a typical winter of −19°F. The middle of the growing ground plans for −33°F, and half of it falls between −34°F and −32°F. The warm end, −30°F to −31°F, is the bench ground around St. Peter, Kasota and Ottawa, the North Mankato rim and Traverse, west of St. Peter. The cold end, −35°F to −36°F, is the floor around New Ulm, Cambria and Good Thunder. The spring layer spreads much wider, from 12°F warmer than Mankato on the valley wall to 5°F colder on the flats northwest of Nicollet.

Why the map looks the way it does

It all hangs on one landform. Between about 11,700 and 9,400 years ago, Glacial River Warren drained Glacial Lake Agassiz through here and cut a valley up to 5 miles wide and about 250 feet deep into a flat till plain. Up top the prairie has 15 feet or less of local relief, with towns at about 990 to 1,030 feet; the floor at Mankato runs 770 to 830 feet. Mount Kato's 240-foot vertical drop is a fair picture of the wall between them.

On a clear, calm night, cold air slides downhill. Near the valley every slope leads into the trench, and five rivers have cut drains for it: the Minnesota past New Ulm and Cambria, the Cottonwood at New Ulm, the Watonwan past Madelia and Garden City, the Le Sueur through deep ravines past St. Clair, and the Blue Earth through a wooded gorge below Rapidan to Mankato's big bend. The valley and the prairie draining into it are one airshed, with the coldest numbers on its floor: −34°F to −35°F within 3 miles of Mankato, North Mankato and Rapidan, and −36°F around New Ulm. When fog filled the valley on August 29, 2011, the National Weather Service put it partly down to cool air draining and settling there.

NOAA station records show the floor pulling away on the worst nights. In an ordinary winter the long-record stations run together, no pair 3°F or more apart in median yearly low. In the January 1977 cold snap, though, New Ulm 2 SE read −37°F, St. Peter −36°F and Mankato −34°F, while St. James read −27°F. In 1995-96 the Mankato station, at 850 feet, bottomed out at −35°F, and the Mankato airport, 170 feet higher, at −32°F.

Above the pool sits the thermal belt. A Hungarian study of 69 clear, calm nights found a valley floor averaged 6.7°F colder than a slope 230 feet higher, and that's about how far North Mankato's town point sits above the river floor; it plans for −31°F against −34°F downtown. The spring layer shows the belt even more: North Mankato reads 9°F warmer than Mankato on a still bloom night, Skyline 11°F and Riverbend Estates, on the steep wall below North Mankato, 12°F. Spring frost pools usually top out 30 to 200 feet up, so the rim mostly sits above them.

Height alone doesn't do it. Out on the flats, away from the valley edge, the cold has nowhere to go. Amboy, at 1,030 feet at the edge of the map, was the coldest station in the 1994, 1996 and 2009 cold snaps, and in 1995-96 New Ulm's airport, at 1,010 feet, bottomed out at about −33°F, the same as New Ulm 2 SE 120 feet lower. Brown County's lakes sit in hollows, many with no inflow or outflow, and a closed hollow fills with cold air to its lowest notch before any spills. What counts is height above the nearest low ground, with somewhere for the cold to drain.

Lakes and towns matter less. Madison Lake covers 1,446 acres and runs 59 feet deep, and its ice still doesn't go out until a median of April 5 or 6; a lake shelters its shore only while it's relatively free of ice (the Wisconsin State Climatology Office's words). Lake Crystal plans for −34°F and Eagle Lake −32°F. Built-up ground gets up to 2.5°F on the map. Snow, about 35 to 40 inches a season, protects roots but chills the air above it.

Mankato: Hilltop, the Highland campus and lower Mankato

Mankato sits on the big bend where the Blue Earth comes in. The town point, downtown on the river bottom at 784 feet and 10 feet above the floor, plans for −34°F, MFTC zone 3b, with a typical winter of −19°F. Within 3 miles the floor has a median of −34°F and the coldest tenth of the growing ground −34°F as well, while the benches and slopes have a median of −32°F.

Minnesota State's Highland Campus sits on the bluff above the valley; the old Valley Campus was down the hill in lower Mankato. The Hilltop planning area runs out to the bluff line west of Crocus Street, so it's upland, and Sibley Park is down on the river. For Old Town and Lincoln Park, type your address in. LeHillier, on the floor southwest of downtown, plans for −34°F and reads 1°F colder at bloom. Skyline, just north of Mount Kato and 210 feet above the floor, plans for −32°F with a typical winter of −17°F and reads 11°F warmer. Riverbend Estates, on a 32 percent slope toward North Mankato, plans for −33°F but reads 12°F warmer, the warmest spring reading of any named place on the map, since the cold drains right past it. Benning, at the foot of the slope north of downtown, plans for −33°F and reads 5°F warmer.

So the hill is where the stone fruit goes. On Hilltop, the Highland side or Skyline, plant Westcot or Sungold apricots, Lapins or Gold sweet cherries (the hardiest sweet cherries we've found) and Siberian C peach. Contender peach (−30°F) is worth a try on the rim; Tom McCamant grows it at Forbidden Fruit Orchard in Paradise, Montana, and it's the only commercial peach we know of that has taken −32°F. Down in lower Mankato or LeHillier, lean on −45°F apples like Haralson, Honeycrisp and Frostbite.

North Mankato and the valley up toward Courtland

North Mankato faces Mankato from the north bank. Its town point sits up top at 1,000 feet, 230 feet above the floor, and plans for −31°F, MFTC zone 3b, with a typical winter of −17°F. That's tied for the warmest planning low of any named place on the map, and it reads 9°F warmer than Mankato at bloom. The river floor within 3 miles has a median of −34°F, so if your lot's down by the river, use that number. Up the valley, Kerns, 190 feet above the floor, plans for −33°F and reads 6°F warmer at bloom, but Avalon, 220 feet up, reads only 1°F warmer, so click your own place. Below them, Judson plans for −34°F, and Cambria, on the floor at 812 feet, −35°F with a typical winter of −22°F. Courtland, on a bench 130 feet up toward New Ulm, plans for −34°F.

North Mankato's −31°F clears −35°F trees with room to spare: Bartlett and Seckel pears, Superior and Italian plums, Black Gold and Lapins cherries, and apricots. On the floor at Judson and Cambria, plant Wealthy, Kindercrisp and Norda apples and Kerr and Trailman applecrabs.

New Ulm, Hermann Heights and the Cottonwood

New Ulm sits on a triangle of land where the Cottonwood meets the Minnesota, with Hermann Heights behind town. The town point, at 892 feet and 90 feet above the floor, plans for −34°F, MFTC zone 3b, with a typical winter of −20°F, and reads 5°F warmer than Mankato at bloom. The floor around it is the coldest around any town on the map: a median of −36°F within 3 miles.

The Cottonwood comes in from the west through Flandrau State Park, just southwest of town, between valley walls 150 to 200 feet high over oxbow marshes and bottomland forest. A side valley like that carries cold onto the main floor on a still night. NOAA's New Ulm 2 SE was the coldest station here in the 1963, 1970, 1974, 1977 and 1983 cold snaps, holds −37°F on several dates, and has the earliest median first fall frost here, September 29. North of town Klossner plans for −34°F, and St. George, 180 feet above its floor, plans for −35°F, tied with Cambria and Good Thunder for the coldest planning low of any named place. That's the station side of the number; the terrain nudge actually warms it a little. South of town, Hanska plans for −32°F and Searles −33°F.

In town, lean on the −40°F list: Haralson, Sweet Sixteen and Zestar!® apples, Ure and Summercrisp pears, Toka and Pipestone plums. The spring reading is good, so Westcot, Debbie's Gold and Morden 604 apricots fit town lots. On the bottoms, at −36°F, stick to −40°F and colder.

St. Peter, Kasota and Traverse des Sioux

Below Mankato the river turns northeast, and St. Peter sits on the floor at 769 feet. It plans for −32°F, MFTC zone 3b, with a typical winter of −20°F, and reads even with Mankato at bloom. Within 3 miles the floor has a median of −33°F, the benches −31°F and the warmest tenth −30°F, and that warm tenth around St. Peter, Kasota and Ottawa is the warmest ground around any town on the map.

Is St. Peter colder than Mankato? Before 1995 it often was: −38°F in the January 1951 cold snap when New Ulm 2 SE read −28°F, and −38°F in January 1972 when Mankato read −31°F, and its −40°F on January 12, 1912 is the area's coldest NOAA reading. Since 1995 it has run about even (−34°F to Mankato's −35°F in February 1996). Our number uses the records since 1995, and St. Peter's station gives a 30-year number of −31°F against Mankato's −34°F, so the map runs St. Peter warmer. On the St. Peter floor, take the room the note at the top talks about.

Traverse des Sioux, the old ford and treaty site a mile north of town, sits on the river bottom at 744 feet, plans for −33°F and reads 4°F colder than Mankato at bloom, the coldest spring reading of any named place along the Minnesota. Ottawa, farther north, plans for −33°F and reads 3°F warmer, and Traverse, up on the prairie west of town, plans for −31°F. Kasota, across the river halfway to Mankato, plans for −32°F and reads 2°F warmer at bloom. It sits on Kasota limestone at or near the surface, so test drainage before you plant. The bench ground here clears Siberian C peach, Red d'Anjou pear, Superior plum and Lapins cherry, and Contender peach is a fair try.

Lake Crystal, Madelia and the Watonwan

West of Mankato is the open till plain, crossed by the Watonwan. Lake Crystal, built around Crystal Lake with Lily, Loon and Mills lakes nearby, sits at 998 feet and plans for −34°F, MFTC zone 3b, with a typical winter of −20°F, a little colder than the floor around it (median −33°F). Madelia, on the Watonwan at 1,028 feet, plans for −33°F and reads 2°F warmer than Mankato at bloom. Upstream, La Salle and Grogan plan for −32°F and read 1°F to 2°F colder at bloom. Downstream, Garden City sits on the Watonwan bottom at 922 feet and plans for −34°F with a typical winter of −21°F. Out here, plan for −34°F on low ground and −32°F on the rises, and give apricots and sweet cherries whatever rise you've got.

Rapidan, Good Thunder, St. Clair and Eagle Lake

South of Mankato the Blue Earth runs in a wooded gorge below Rapidan Dam, which partly failed in the June 24, 2024 flood. Rapidan, on a bench 130 feet above the floor, plans for −33°F, with a floor median of −35°F around it. Good Thunder plans for −35°F with a typical winter of −21°F, but reads 3°F warmer than Mankato at bloom. The Le Sueur comes west past St. Clair, its lower course in deeply cut ravines that carry cold down at night; St. Clair, at the foot of a slope, plans for −34°F. Eagle Lake, east of Mankato at 1,012 feet, plans for −32°F with a typical winter of −19°F and reads even with Mankato at bloom. Farther east, Owatonna, Faribault and Northfield have their own map.

Nicollet and the prairie north of the river

North of North Mankato, Nicollet County's prairie slopes gently east; its high point, about 1,065 feet, is the lowest county high point in Minnesota. Nicollet plans for −32°F with a typical winter of −19°F, and the coldest tenth of the ground within 3 miles plans for −35°F. Swan Lake, a shallow lake where trumpeter swans nest, is nearby. On a still spring night this flat country reads colder than Mankato: Oshawa by 2°F, Nicollet Landing by 3°F and Poor Farm Landing by 5°F, the coldest spring reading of any named place. Plant apples, haskap and currants, and put plums on any rise. North toward Hutchinson and Glencoe, the Crow River map covers you.

Spring frost and bloom in the Minnesota River Valley

Bloom-night frost follows the same drainage, only sharper, and open blossoms of apple, pear, cherry, peach, apricot and plum all start dying near 28°F.

NOAA's 1991 to 2020 records put the median last 32°F between April 28 at St. James and May 3 at St. Peter, with Mankato on April 29. The last 28°F comes earliest at Mankato (April 15, which fits town heat, though we haven't found a local study) and latest at New Ulm 2 SE (April 24). One spring in 10 the last 32°F comes as late as May 15 to May 17, and the frost-free season runs 152 to 156 days. St. Peter has the latest last frost but also the latest first fall frost (October 5), so its season matches Mankato's 153 days, just shifted later.

Madison Lake's latest ice-out, April 30, 2018, ended the coldest April on record in southern Minnesota. We haven't found any record of these lakes holding bloom back the way the Great Lakes do. Minnesota's Extension fruit people say the state has historically escaped a lot of spring frost by blooming later than the rest of the Midwest, but in 2026 two freezes did nearly 80 percent blossom damage at the university's research center near Chaska, worst on mid-bloom varieties and on trees low on the slopes.

So put apricots, peaches and sweet cherries where spring reads warm (North Mankato, Skyline, Kerns, Benning, New Ulm, Good Thunder, Ottawa) and apples, haskap and bush fruit on the floors and flats. Only about 15 percent of apple blossoms need to set for a crop, and fully open haskap flowers take 19°F; most fruit can lose half its blossoms with negligible effect. Through bloom, mow under 2 inches, don't till, and water a day or two before a frost night.

What the weather records say

NOAA station records here go back to 1894. The coldest reading on file is −40°F at St. Peter on January 12, 1912. New Ulm 2 SE holds −37°F, first set on February 19, 1929. In the February 2, 1996 outbreak Amboy read −36°F and Mankato −35°F, Mankato's record. The average yearly low runs −24°F at St. Peter and New Ulm 2 SE and −22°F at Mankato.

Our typical winter runs −17°F on the North Mankato rim, −19°F at Mankato and −20°F at New Ulm and St. Peter, the kind of average USDA's zones are built on; we couldn't confirm USDA's 2023 zone town by town. Our zones run about a full zone colder 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.

What you can grow in south-central Minnesota's river country

Every plant we sell is zoned to the coldest temperature it has actually come through. Match that to your planning low, then think about bloom. Most of these want a pollenizer nearby, and our pollination maps show which varieties pair up.

The rim, the benches and the St. Peter stretch: −30°F to −32°F

North Mankato, Skyline, Avalon, Traverse, St. Peter, Kasota, Hanska, Eagle Lake and the benches along the valley.

• Apples: Honeycrisp, Haralson, Zestar!®, Snowsweet®, Golden Russet, Empire
• Pears: Bartlett, Seckel, Red d'Anjou, Ure
• Plums: Superior with Toka (Toka is a good pollenizer for Superior), Italian
• Cherries: Lapins, Gold and Black Gold where spring reads warm; Evan's Bali tart cherry
• Apricots and peaches: Westcot and Sungold apricots; Siberian C peach, the hardiest peach we think is out there (it ripens very late); Contender worth a try on the warmest lots
• Grapes and berries: Marquette and Frontenac grapes, Boyne raspberry

Most towns and the prairie: −32°F to −34°F

Downtown Mankato, New Ulm, Lake Crystal, Madelia, Nicollet, Courtland, Rapidan, Kerns, Ottawa, Judson, St. Clair and most of the farm ground.

• Apples: Wolf River, Frostbite, Honeycrisp, Haralson, Cortland; Centennial applecrab (Ed Schultz saw zero winter injury on it after a winter that hit −47°F)
• Pears: Ure, Summercrisp, Cold Snap®
• Plums: Toka, Pipestone, Underwood
• Cherries: Evan's Bali and Meteor tart cherries, Romeo and Juliet dwarf cherries; Lapins and Gold only on the higher lots
• Apricots and peaches: Westcot, Morden 604 and Debbie's Gold where spring reads warm; Siberian C clears −34°F with a degree to spare
• Berries and vines: Honeyberry, Montana Black Currant, Red Lake currant, Pixwell gooseberry, Valiant grape

Cold floors and the coldest corners: −34°F to −36°F

The floor around New Ulm, Cambria, Good Thunder, St. George, Klossner, LeHillier and the Watonwan, Blue Earth and Le Sueur bottoms. In the 1995-96 winter that set Mankato's record, Minnesota's best apple survivors (Rescue, Dolgo, Chestnut and Centennial) came from plots that saw −50°F to −55°F.

• Apples and crabs: Kindercrisp, Norda, Wealthy, September Ruby; Rescue, Trailman, Kerr and Chestnut applecrabs, Dolgo crabapple. If you only plant one tree, make it Kerr or Trailman.
• Plums: Brookgold and Brookred, on whatever rise you have; keep pears up off this ground, since they bloom early
• Cherries: Cutie Pie dwarf cherry, Nanking Cherry, and Evan's Bali, good to at least −40°F to −45°F
• Berries: Honeyberry, Golden Currant, Montana Black Currant (we've never seen winter damage on it), Aronia Berry, Success serviceberry

Roots, snow and timing

Roots are the weak link. At Ed Schultz's farm in Gallatin Gateway, Montana, Bud 118 apple rootstock has seen near −50°F with no damage, under snow, and 4 to 10 inches of snow insulates soil well. Where wind strips the prairie, hold snow with a windbreak around 30 to 40 percent dense, never across the low side of the trees. Test drainage on clayey till, bottomland and Kasota's limestone: dig 2 feet, fill it, let it drain, refill, and under 10 hours is well drained. In zone 4 and colder we taper water from mid-August so trees harden off before the early freezes. Local troubles on record: frost in low spots, blight (the old Mankato Nursery marked some apples "liable to blight"), floods on the bottoms and tornadoes, like the 1998 one that leveled nearly 2,000 trees at Gustavus in St. Peter.

Fruit history here

Mankato had its own nursery more than a century ago. Around 1909 or 1910, L. Z. Smith's Mankato Nursery promised "only the very hardiest of the IRON CLAD VARIETIES" for the Northwest: Duchess, Hibernal, Wealthy, Wolf River, Malinda, Northwestern Greening and more, with Transcendent and Whitney crabs, plums, sand cherry, juneberry and buffalo berry. Later lists added Golden Russet and the Hansen plums, Hanska among them, which it said would grow "anywhere a willow will grow," and allowed that pears and peaches "will do alright in some localities."

We still sell a good piece of that list: Wealthy, Wolf River, Malinda, Northwestern Greening (we list it as Northwest Greening), Golden Russet, Transcendent and Whitney crabs, the Hanska plum, Sand Cherry, Serviceberry and Buffaloberry. New Ulm's founders laid out four-acre garden lots around town, and Morgan Creek Vineyards at New Ulm, founded in 1993, makes a Marquette and uses Minnesota's cold-hardy grape varieties.

Questions people ask

What growing zone is Mankato, MN?

Mankato plans for −34°F, MFTC zone 3b, with a typical winter of −19°F. USDA's zones are built on an average winter's coldest night, so they read warmer; ours is built on the bad night we plan for. North Mankato plans for −31°F and St. Peter −32°F, both zone 3b.

When is the last frost in Mankato?

NOAA station records for 1991 to 2020 put Mankato's median last 32°F on April 29 and its last 28°F on April 15. Across the area the median last 32°F runs April 28 to May 3, and one spring in 10 it comes as late as May 15 to May 17.

Is St. Peter colder than Mankato?

In the big outbreaks before 1995, often: St. Peter read −38°F in the January 1972 cold snap when Mankato read −31°F, and it holds the area's coldest NOAA reading, −40°F in 1912. Since 1995 they've run close, and our map plans St. Peter at −32°F against Mankato's −34°F.

What hardiness zone is New Ulm, MN?

New Ulm plans for −34°F, MFTC zone 3b, with a typical winter of −20°F. The floor around town runs colder, a median of −36°F, and the New Ulm 2 SE station holds −37°F on several dates.

Can you grow peaches in southern Minnesota?

Yes, with the right variety in the right spot. Siberian C peach has come through −35°F, which clears the planning low on most of this map, and Contender (−30°F) is worth a try on the warmest ground, like the benches around St. Peter and Kasota or the North Mankato rim.

Where are the frost pockets around Mankato and New Ulm?

The river floors and the flat, low prairie. The floor around New Ulm plans for −36°F, and on a still bloom night Traverse des Sioux reads 4°F colder than Mankato and Poor Farm Landing, northwest of Nicollet, 5°F colder. The rim is the warm ground: North Mankato and Skyline read 9°F and 11°F warmer.

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.