Fruit Trees for Marshalltown, Grinnell and Tama, Iowa

On January 16, 2009, the NOAA station on the Iowa River bottom at Marshalltown read −34°F. The Marshalltown airport, 3 miles north and roughly 100 ft higher on the upland, read −28°F that same morning. That's 6°F in 3 miles of country most people would call flat, and it's why picking fruit trees for Marshalltown, Grinnell and Tama starts with where your place sits.

The map covers parts of Marshall, Tama, Poweshiek and Jasper counties in central Iowa: the Iowa River valley from Marietta and Albion down through Marshalltown, Le Grand and Tama-Toledo, the northern Tama County uplands, and the southern uplands around Grinnell, Newton and Kellogg. 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

Every number is a 30-year planning low, the same number our cold hardiness calculator uses, built from NOAA station records since the 1995-96 winter, adjusted for the lay of the land and set on the safe side. It isn't the record. 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 zones are built on, which is why theirs read warmer. The spring layer shows how much warmer or colder a spot runs than downtown Marshalltown on a still, clear night at bloom.

Marshalltown, the reference town, plans for −32°F (MFTC zone 3b) with a typical winter of −16°F. The middle of the growing ground plans for −31°F, and nine tenths of it falls between −33°F and −28°F. The warm end is in the south: Sheridan, Newton and Metz −27°F (zone 4a). The cold end is the Iowa River and its creeks: Marietta and Ferguson −33°F, Minerva −32°F, the river bottom at Marshalltown's NOAA station −34°F (zone 3b). The spring layer runs from 8°F colder than downtown Marshalltown at Marietta to 3°F warmer at Oakland Acres.

Why the map looks the way it does

Three glacial landscapes meet here: young, flat drift with kettle holes and sloughs on the north and west edges of Marshall County, and older drift under thick loess nearly everywhere else, cut by streams into rolling uplands and sharp V-shaped valleys. In Marshall County the uplands stand only 50 to 100 ft above the lowlands, but on a clear, calm night that's plenty. Cold air made on the uplands slides down Linn, Timber, Minerva and the other creeks to the Iowa River, and down Rock Creek and the North Skunk in the south. The lowest towns (Marshalltown, Le Grand, Montour and Tama on the river; Kellogg and Murphy in the south) sit along those floors, and the floors are where the map puts its cold.

The map also runs colder from south to north, and the stations agree. Over 74 years of NOAA station records, Marshalltown's river-bottom station has run a median 4°F colder than Newton on the year's coldest night, and Grinnell 3 SW 3°F colder over 69 years. On February 3, 1996, Marshalltown and Grinnell 3 SW both read −35°F while Newton read −26°F. Part of it is the river, the biggest, lowest floor here. Part is Newton's setting: its station sits on flat upland with most of the ground around it lower, so cold drains away, and the town is bench ground 110 ft above its floor.

The river valley averages 1 to 2 miles wide through Marshall County, then squeezes through a limestone gorge less than a quarter mile wide at Le Grand. Cold air pools above a narrows the way water backs up behind one, and the bottom upstream around Marshalltown is where the map and the stations find some of the deepest cold: −34°F at the river-bottom station's spot, against −32°F in town 65 ft higher and −29°F at the airport. Nobody has measured whether the gorge is part of the cause, but it fits.

Height above the nearest low ground matters more than elevation. Murphy and Metz, south of Newton, sit within 5 ft of each other in elevation. Murphy, on the valley floor, plans for −30°F and runs 7°F colder than downtown Marshalltown at bloom; Metz, on a 10 percent hillside where the cold drains past, plans for −27°F and runs a degree warmer. That hillside band 60 to 110 ft above the creek, where Oakland Acres and Kellogg sit, is the thermal belt here; Utah State's extension people say ground 50 to 100 feet above the valley floor is less freeze prone. The flip side is the draw, like the creek channel at Lambs Grove.

Water doesn't help. Rock Creek Lake near Kellogg, about 466 acres and under 18 ft at its deepest, freezes over for ice fishing, and a river floor is still a floor. Towns help some. And the kettle holes and sloughs of western Marshall County, the prairie sloughs in its northeast corner and boggy Snipe Creek are the likeliest frost pockets on flat ground: low, grassy, often organic ground that runs cold on a still night.

Marshalltown: downtown, the Iowa River bottom and Linn Creek

Marshalltown was platted in 1853 on rolling prairie between the Iowa River on the north and Linn Creek on the south, and that rise is the town's microclimate in a sentence. Downtown sits at about 936 to 939 ft, roughly 65 ft above the river floor, and on a still night the cold drains off it both ways. Downtown plans for −32°F (zone 3b), typical winter −16°F, and it's the zero point for the spring layer. The floor within 3 miles plans for −34°F, the bench ground −31°F.

The river side (Riverview Park, Riverside Cemetery and the Iowa Veterans Home grounds on the south bank, and Nicholson Ford Woodland's river-bottom trails) runs down onto the same kind of bottom the NOAA station sits on. If your ground is down there, plan for −34°F and 8°F colder than downtown at bloom; it's also the ground that floods. The industrial strip along the railroad and Linn Creek is a second, smaller drainage. The Historic Main Street District, the 13th Street District and the old houses west of downtown share the rise. The postwar neighborhoods south along Center Street to Olive Street and the Elmwood Country Club area climb onto upland around 935 to 965 ft, which should run a little milder than the bottoms (nobody has measured it).

At −32°F, plant trees that have come through −35°F or colder: Haralson (−45°F) and Honeycrisp (−45°F) apples, Lapins sweet cherry (−35°F), Superior plum (−35°F) with Toka to pollenize it, and on the rise, Westcot apricot (−45°F) and Siberian C peach (−35°F). Contender peach (−30°F) is worth a try on the best ground off the bottoms.

Albion, Marietta and the Iowa River above Marshalltown

Northwest of Marshalltown the river runs through a broad bottom with sand flats, and windblown sand lies up to 36 ft deep at Marietta Sand Prairie. Marietta, on the river bottom 10 ft above the floor, is the coldest named spot on the map: −33°F (zone 3b) and 8°F colder than downtown Marshalltown at bloom. Minerva, 10 miles northwest of town, is nearly as cold at −32°F and 7°F colder at bloom; Minerva Creek drains more than two-thirds of the county's young, poorly drained drift.

Get up out of the bottom and it changes fast. Albion, 70 ft above its floor, plans for −30°F and runs only a degree colder than downtown Marshalltown at bloom, while its floor plans for −32°F. Bangor (−30°F), on a bench 100 ft up, reads even with downtown at bloom, the best early-bloomer ground up here; Liscomb (−30°F) runs 3°F colder. Firm, moist soil stores the day's heat and gives it back at night and loose, dry sand doesn't, so water sand plantings a day or two before a bloom-night frost. Farther west, our Ames and Des Moines map picks up.

Tama, Toledo, Montour and Le Grand

Below Marshalltown the river passes Quarry, the old LeGrand Quarry Co. village, then cuts through the limestone at Le Grand. Le Grand sits up out of the gorge, 80 ft above the floor: −31°F (zone 3b), 2°F colder than downtown Marshalltown at bloom. Quarry, 40 ft above the floor, is the same −31°F but 5°F colder at bloom. Timber Creek's shelf, 15 to 20 ft above its floodplain in Le Grand Township, is the kind of small step that helps at bloom.

In Tama County the floodplain widens to about 2 miles. Tama sits on its north edge, only 10 ft above the floor, and the ground climbs to 900 to 915 ft toward Toledo, 2 miles north. In winter the map barely tells them apart: both plan for −31°F (zone 3b), with typical winters of −16°F and −17°F. The spring layer, which takes the terrain at full strength, does. Tama runs 6°F colder than downtown Marshalltown on a bloom night; Toledo, on a 4 percent toe slope 60 ft up, runs even with it, and the bench ground within 3 miles of Toledo plans for −29°F. Even the upland isn't frost-safe: the Toledo 3N station, on a ridge 3 miles north, has only 158 frost-free days.

Montour, 7 miles up the valley, is valley floor: −32°F and 6°F colder than downtown Marshalltown at bloom. The Meskwaki Settlement, about 4 miles west of Tama, takes in Iowa River bottom that should frost the same way. On these bottoms plant apples, honeyberries and currants. On Toledo's slopes, Lapins, Westcot and Siberian C all clear the number, and Evan's Bali tart cherry (−45°F) has room to spare.

Gladbrook, Garwin and the northern Tama County uplands

This is home ground for Tama silt loam, Iowa's representative state soil, deep, well-drained prairie loess with its type location about 3 miles north and a mile west of Gladbrook. Gladbrook, on a 5 percent toe slope 30 ft above its floor, plans for −32°F (zone 3b), typical winter −18°F, and runs only a degree colder than downtown Marshalltown at bloom. Its floor plans for −32°F and its warmest tenth −30°F. Garwin, right at the level of its floor, is the frost spot: −32°F in winter and 6°F colder than downtown Marshalltown at bloom. Plant like Marshalltown on Gladbrook's slopes and like the river bottoms around Garwin. Farther north, our Waterloo and Cedar Falls map picks up.

Grinnell, Malcom and the Poweshiek County uplands

Grinnell sits on high upland, downtown at about 1,013 ft, and it's on the warm side of the map: −29°F (zone 4a), typical winter −13°F. The ground falls away into draws, though, and the coldest tenth within 3 miles plans for −32°F. If your yard near downtown, Central Park or the college is on the flat, use −29°F; if it slopes into a draw, plan nearer −32°F. At bloom Grinnell reads 3°F colder than downtown Marshalltown, since flat upland makes its own cold on a still night.

The NOAA station called Grinnell 3 SW shows what a draw does. It sits a couple of miles southwest of downtown at about 915 ft, at the bottom of a draw roughly 70 ft below the farmland around it and 100 ft below town. Its median last 32°F is May 6, against April 17 at Newton, and it read −34°F in 1974 and 1979 and −35°F in 1996. The map reads that spot at −32°F, warmer than the station's own 30-year number of −33°F. The winter number takes fine-scale terrain at only a quarter strength, so a narrow draw can run colder than the map shows; if you're in one, plan colder than your number.

Sheridan (−27°F, one of the warmest named spots) and Newburg (−30°F) are flat upland like Grinnell. Oakland Acres, on a hillside 110 ft above its floor 5 miles west of Grinnell, plans for −29°F and runs 3°F warmer than downtown Marshalltown at bloom. Malcom, on a toe slope 9 miles east, plans for −31°F but runs a degree warmer at bloom. On Grinnell's flat, trees rated −30°F fit: Rainier cherry, D'Anjou pear, Liberty apple and Contender peach. Blushingstar peach (−25°F), which came through −25°F at our place on January 13, 2024, is worth a try against a south wall in town.

Newton, Kellogg and Rock Creek

Newton sits on bench ground 110 ft above its floor and plans for −27°F (zone 4a), typical winter −14°F, even with downtown Marshalltown at bloom. Its floor plans for −30°F, so in Downtown Newton, the First Avenue East district or out by Fred Maytag Park, how far your lot sits above the nearest creek matters more than which district it's in. The Newton station has the longest frost-free season in the map at 179 days, and its coldest is −31°F on January 10, 1982, over 83 years on record. Lambs Grove, on a creek channel 1.4 miles west, plans for −28°F and runs 7°F colder at bloom.

Kellogg, on a 9 percent hillside 60 ft above its floor near Rock Creek, plans for −30°F and runs 2°F warmer than downtown Marshalltown at bloom; its warmest tenth plans for −28°F. Just off the southwest corner, the Neal Smith National Wildlife Refuge station near Prairie City has a 179-day frost-free season and a coldest reading of −21°F in 22 years. The hillsides around Kellogg and Oakland Acres are the best apricot ground in the south half: Harlayne (−30°F) and Montana Mango (−35°F).

Melbourne, Laurel, Gilman and southern Marshall County

South of Marshalltown the towns sit on high loess upland: Van Cleve at 1,049 ft, Melbourne 1,047 ft, Laurel 1,040 ft, Gilman 1,031 ft. Laurel (−30°F) and Gilman (−29°F) are zone 4a and Melbourne (−31°F) is 3b, but the valleys between run colder: the floor within 3 miles of Laurel plans for −33°F. Flat high ground still makes its own spring frost; Van Cleve runs 5°F colder than downtown Marshalltown at bloom. Ferguson and Haverhill, on toe slopes 30 to 50 ft above their floors, plan for −33°F and −32°F. Pickering (−30°F) and Dillon (−31°F), 80 to 100 ft above their floors, read within a degree of downtown at bloom. Put early bloomers on slopes like those, not on flat tops or valley floors.

Spring frost and bloom in the Iowa River country

The spring layer follows the same drainage as winter, only sharper. The river and creek bottoms (Marietta, Murphy, Minerva, Lambs Grove, Montour, Tama, Garwin) read 6°F to 8°F colder than downtown Marshalltown on a still, clear bloom night, and the hillsides read warmest (Oakland Acres 3°F warmer, Kellogg 2°F). That's an 11°F spread, and NC State's fruit people point out that 3°F to 4°F can separate no crop from a full one. With no big lake to hold bloom back, site is the main lever.

NOAA station records for 1991 to 2020 put the median last 32°F at April 17 at Newton, April 28 at Marshalltown, April 29 at Toledo 3N, April 30 at the Marshalltown airport and May 6 at Grinnell 3 SW. The last 28°F, about where open blossoms start dying, comes April 10 at Newton and April 25 at Grinnell 3 SW. One year in ten the last 32°F comes as late as May 5 at Newton, May 13 at Marshalltown and Toledo 3N, and May 18 at Grinnell 3 SW. The frost-free season runs from 179 days at Newton to 150 at Grinnell 3 SW.

Appleberry Farm in Marshalltown lost a significant part of its 2026 apple crop to a late frost during blossom. That spring Iowa State's Suzanne Slack warned that early warmth pushes buds ahead and that freeze risk runs into early May. In 2012, after a warm March, two freezing nights on April 10 and 11 took Iowa State's Horticulture Research Station near Gilbert, about 30 miles west, down to 20°F, and staff expected little apple crop.

Site comes first; the FAO's frost protection manual calls it the single most important method of frost protection. Put apricots, peaches, plums and sweet cherries on hillsides and toe slopes that read even with or warmer than downtown Marshalltown, apples a step lower, and honeyberries (haskap, whose open flowers take 19°F) and currants down on the colder ground. A north slope holds early bloomers back, and an east slope is ideal. A windbreak, fencerow or road fill across the slope backs cold air up into the trees just above it. Only about 15 percent of apple blossoms need to set for a crop, so a frost that looks like a disaster often just thins the tree.

What the weather records say

The three longest NOAA station records here all hit bottom the same morning: −35°F at Marshalltown's river-bottom station on February 3, 1996 (123 years on file), −35°F at Grinnell 3 SW on February 3 and 4, 1996 (111 years) and −34°F at Toledo 3N on February 3, 1996 (127 years). The Marshalltown airport, on record since 1997, bottomed out at −28°F on January 16, 2009. The local paper recounts 133 straight hours below 0°F in February 1936, and on January 30, 2019, Marshalltown's high was −15°F.

The early and late outbreaks do the most harm to fruit. On March 1, 1962, Marshalltown read −32°F, at the tail of winter when a warm spell can already have stripped some hardiness. The Armistice Day freeze of November 11, 1940 left Iowa's 1941 apple crop at about 15 percent of normal, because trees that haven't hardened off die at temperatures they'd shrug off in January.

USDA's 2023 map puts the Marshalltown, Tama and Toledo ZIP codes in zone 5a (−20°F to −15°F) and Grinnell and Newton in 5b (−15°F to −10°F). Those match our typical winters (−16°F to −17°F along the river, −13°F to −14°F at Grinnell and Newton), since USDA's zones are built on the average winter's coldest night. Our planning lows sit 13°F to 16°F below those, a zone and a half colder, which fits NOAA station records showing the worst night in about 30 winters runs a median 13°F below a station's average winter low.

What you can grow here

Match the tree to your own number from the box on the map. Toka (−45°F) pollenizes Superior; the pollination maps show which other trees pair up.

Grinnell, Newton and the southern uplands: −27°F to −30°F

• Apples: Honeycrisp (−45°F), Cortland (−40°F), Liberty (−30°F), Enterprise (−30°F).
• Pears and plums: Bartlett (−35°F), D'Anjou (−30°F), Toka with Superior, Stanley (−30°F).
• Cherries: Lapins (−35°F), Rainier (−30°F), Meteor tart (−40°F).
• Apricots and peaches, on hillsides: Harlayne (−30°F), Montana Mango (−35°F) and Contender (−30°F; 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).
• Worth a try on the warmest lots in Grinnell and Newton: Blushingstar peach (−25°F).

Marshalltown, Tama-Toledo and the middle ground: −29°F to −32°F

• Apples: Haralson (−45°F), Honeycrisp, Zestar!® (−40°F), Red McIntosh (−40°F).
• Pears: Ure (−40°F), Luscious (−40°F).
• Plums: Toka and Superior, Kahinta (−40°F), Italian (−35°F).
• Cherries: Lapins (−35°F; a grower of ours in Cowley, Wyoming saw no damage at −33°F), Gold (−35°F), Evan's Bali tart (−45°F).
• Apricots and peaches, on slopes only: Westcot (−45°F), Sungold (−40°F), Siberian C (−35°F).
• Grapes: Marquette (−35°F), Frontenac (−35°F).
• Worth a try on the best ground: Contender, Rainier and D'Anjou (all −30°F).

The Iowa River bottoms, the draws and the coldest pockets: −32°F to −34°F

Most of these spots also read 6°F to 8°F colder than downtown Marshalltown at bloom, so lean on apples and bush fruit and skip apricots, peaches and sweet cherries.

• Apples and applecrabs: Haralson, Frostbite (−45°F), Wealthy (−50°F), and Kerr (−50°F) or Trailman (−60°F); if you only plant one tree, make it one of those two. Centennial (−50°F) showed zero winter injury at Ed Schultz's in Gallatin Gateway, Montana after a winter that hit −47°F.
• Pears: Krasnobokaya (−50°F), Ure (−40°F).
• Bush fruit: Honeyberry (−50°F), Montana Black Currant (−50°F), Red Lake currant (−40°F), Aronia Berry (−50°F), Boyne raspberry (−40°F).

Roots are the weak link. Dormant apple roots are seriously injured near 10°F while the wood above can take about −40°F, and snow is what keeps them alive; at Ed Schultz's, Bud 118 rootstock has seen near −50°F with no damage under snow. Open Iowa upland loses its snow to wind, so mulch and hold snow with a windbreak on the windward side. Pick a 4 to 8 percent slope off the floor, as Montana State recommends, and taper water from mid-August so trees harden off. Slough ground drains poorly, and the river bottoms flood (the Iowa River at Marshalltown crested above 21 ft in 2008, 2013 and 2014). After the 2018 tornado and 2020 derecho, stake young trees. Iowa State's PM 453, Fruit Cultivars for Iowa, sorts varieties by the state's climate regions.

Fruit history here

Iowa was a leading apple state in the early 1900s, second only to Michigan, and the Armistice Day storm of 1940 badly damaged the industry. Apples are coming back: in 2022 Iowa had 498 apple farms on 1,323 acres, up from 428 farms on 943 acres five years earlier. Today the Mason family's Appleberry Farm in Marshalltown grows Honeycrisp, Cortland, McIntosh, Jonathan, Wealthy, Enterprise and more for u-pick; Hinegardner Orchard is at Montour, and John Ernest Vineyard and Winery near Tama looks out over the Iowa River valley.

Questions people ask

What hardiness zone is Marshalltown, Iowa?

USDA's 2023 map puts Marshalltown in zone 5a, −20°F to −15°F. Our map has downtown Marshalltown planning for −32°F, MFTC zone 3b, with a typical winter of −16°F, and the Iowa River bottom at −34°F. USDA's zone is based on an average winter, ours on the bad night we plan for.

What growing zone is Grinnell, Iowa?

USDA's 2023 map has Grinnell and Newton in zone 5b, −15°F to −10°F. Our map plans for −29°F in Grinnell and −27°F in Newton, both MFTC zone 4a, with typical winters of −13°F and −14°F. The draws around Grinnell run colder: the NOAA station in one southwest of town has a 30-year number of −33°F.

When is the last frost in Marshalltown?

NOAA station records for 1991 to 2020 put the median last 32°F on April 28 at the Marshalltown station and April 30 at the airport, and one year in ten it comes May 13 to May 16 or later. The river bottom also runs about 8°F colder than downtown on a still bloom night, so hold tender plants there until mid-May.

Why does Grinnell's weather station show such late frosts?

The Grinnell 3 SW station sits at the bottom of a draw a couple of miles southwest of town, about 100 ft below downtown, where cold air pools on calm nights. Its median last 32°F is May 6, almost three weeks after Newton's April 17. Gardens up on the flat in town should see their last spring frost sooner, though nobody has measured it.

Can you grow peaches in central Iowa?

Yes, with the right tree and spot. Contender (−30°F) clears the planning lows around Grinnell, Newton and Kellogg, and Siberian C (−35°F) clears the planning low on nearly all of this map. Peaches bloom early, so put them on a hillside or toe slope like Oakland Acres, Kellogg or Toledo, never in the Iowa River bottoms.

What fruit trees grow in Marshalltown, Iowa?

Apples are the safe bet, and Appleberry Farm in town grows Honeycrisp, Cortland and Wealthy. At Marshalltown's −32°F, plant trees rated −35°F or colder: Haralson and Honeycrisp apples, Lapins cherry, Superior plum with Toka, and Westcot apricot and Siberian C peach on the higher ground. Contender peach and Rainier cherry (−30°F) are worth a try on the best ground.

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.