Fruit Trees for Dubuque, Galena and the Mississippi Bluffs, Iowa and Illinois

On January 17, 2009, NOAA's station at Lock and Dam 11, on the Mississippi at Dubuque, read −37°F, the coldest reading on file at any station in or around this map. In the same cold snap the airport station, 420 feet higher on the upland south of town, read −30°F. Yet the river station also gets the longest frost-free season here, 190 days to the airport's 163. Growing fruit trees for Dubuque, Galena and the Mississippi bluffs means knowing which cold you face and where it settles. The map covers the Tri-State Area in the Driftless: Dubuque, Asbury, Peosta and the Dubuque County ridge towns, Bellevue and St. Donatus, Galena and East Dubuque in Jo Daviess County (Galena Country), and Dickeyville, Hazel Green and Cuba City in southwest Wisconsin.

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 same number our cold hardiness calculator uses, nudged for the ground around you: a safe number to plan on, 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. The spring layer shows how much warmer or colder a spot runs than downtown Dubuque on a still, clear night at bloom.

Downtown Dubuque, our reference, plans for −33°F, MFTC zone 3b, with a typical winter of −16°F. The middle of the map's growing ground plans for −32°F, and half of it falls between −33°F and −31°F. The warm end, zone 4a, is mostly high ground: King and Bremen (in a draw near Galena) at −28°F, Balltown, Rickardsville and the Centennial Cross bluff south of downtown at −29°F. The cold end, zone 3a, is low ground: Rodden, out toward Hanover, at −37°F, Etna at −36°F and the mouth of the Little Maquoketa at −35°F.

Why the map looks the way it does

This is the Driftless Area, the corner of Iowa, Illinois and Wisconsin the ice sheets never flattened: a loess-capped bedrock plateau cut by deep valleys. The Mississippi runs at about 590 to 620 feet here and the uplands reach 1,100 to 1,210 feet. On a clear, calm night the uplands lose their heat to the sky, and the chilled air slides down the coulees and creek valleys (the Galena River canyon, Catfish Creek to the Mines of Spain, the Little Maquoketa, Mill Creek at Bellevue) to pool on the floor of the Mississippi trench and in the flat bottoms of the side valleys.

The stations show it. In the January 30, 1951 cold snap the airport, on the plateau at 1,040 feet, read −21°F while Lock and Dam 11 read −31°F. In the February 1996 cold snap the airport read −27°F, Bellevue's dam station −34°F and the Elizabeth station, in a valley just east of the map, −35°F. That's 7°F to 10°F between plateau and floor on the big nights; in an ordinary year the long-record stations all average a yearly low of −16°F to −19°F. The order isn't fixed: in the January 21, 1970 cold snap the airport read −28°F against −22°F at the dam. On windy or cloudy nights the pattern flattens or flips and higher ground runs colder, but the clear, calm night is the one that does the damage at bloom.

Within 3 miles of most towns, the benches 100 to 700 feet up plan 3°F to 4°F warmer than the floor, and around Bellevue 5°F. That's the thermal belt, where the cold keeps draining past; a Hungarian study of 69 clear, calm nights found a valley floor averaging 6.7°F colder than a slope 230 feet higher. Height on the plateau isn't enough by itself. The upland has its own shallow valleys, and a wide floor that drains slowly pools hard. Etna, on a flat floor at 761 feet, plans for −36°F. O'Neill, 10 feet above its little floor, plans for −34°F, while Rickardsville, 1.8 miles south and 220 feet above its floor, plans for −29°F.

The river is the puzzle. Lock and Dam 11 holds the coldest reading and the longest season (median last 32°F April 14, first October 21, against April 30 and October 10 at the airport). Open water holds heat, the river stays open all winter at Lock and Dam 12 (Iowa DNR), and river fog can delay a freeze. But Bellevue's dam station gets 166 frost-free days, about the same as the airport, and we haven't found a published explanation for the Dubuque dam's long season. A river floor is still a floor, frozen water does nothing for its shore, and you shouldn't count on a reservoir like Lake Galena.

Shelter cuts both ways: Bellevue's bluffs shield its riverfront from harsh winds, and a spot out of the wind also stays calm and cold. Dubuque averages 42.5 inches of snow, and that matters: dormant apple roots are seriously hurt near 10°F, and North Dakota State measured 31°F a foot down under snow with the air at 4°F; after the snowless 2024-25 winter, Wisconsin's fruit program found damage just below the graft union. South slopes bloom earlier, into frost season. And a few north slopes are algific talus slopes, rare habitat that breathes cold, damp air all summer; more than half the world's are in the Driftless, mostly in northeast Iowa.

The spring layer follows the same drainage at full strength, sharper, since spring frost pools usually top out 30 to 200 feet up. Bremen, just southeast of Galena, plans for −28°F, tied for the warmest planning low of any named place, but it sits in a draw and reads 2°F colder than downtown at bloom. Frith Spur, on the flats north of Dubuque, reads 9°F colder, the coldest spring reading of any named place on the map.

Downtown Dubuque, the North End and the river flats

Downtown sits on the river plain, 20 to 30 feet above the floor: −33°F, MFTC zone 3b, typical winter −16°F, with the floor within 3 miles at −34°F and the benches at −31°F. Pavement and buildings hold a little heat on still nights, and the flats around it run a degree colder: the Millwork District, the Washington Neighborhood, the Port of Dubuque and South Port plan for −34°F and read 1°F colder at bloom, Jackson Park −33°F and 2°F colder, and Ice Harbor, on the water at 596 feet, −34°F and 5°F colder. Cable Car Square, at the foot of the bluff, plans for −32°F and reads 2°F warmer.

The North End is low and flood-prone, and the flats north toward the Little Maquoketa run cold: Eagle Point −34°F and 4°F colder at bloom, Edmore −33°F and 5°F colder, Frith Spur −33°F and 9°F colder. The Little Maquoketa's mouth, at 604 feet, plans for −35°F, zone 3a. Across the river, East Dubuque (the old Dunleith) plans for −32°F, typical winter −16°F, but reads 7°F colder than downtown at bloom; its benches plan for −31°F.

On the flats, plant for −34°F and cold bloom nights: Haralson, Honeycrisp and Wolf River (−45°F), Zestar!® (−40°F) and Freedom (−35°F) apples, Evan's Bali tart cherry, honeyberry and Montana Black Currant. Put anything tender by a south or west wall; town trees bloom earlier, with less winter risk and more spring risk.

Dubuque's bluffs: the South End, West End, Valley View and Key West

The South End, with its old-money homes near the Mines of Spain, sits 200 feet above the floor: −30°F, MFTC zone 4a, typical winter −13°F, 8°F warmer than downtown at bloom. Rockdale, on a steep slope 110 feet up, plans for −32°F but reads 10°F warmer, since the cold slides right past it. Key West, on the upland toward the airport, plans for −31°F and reads 9°F warmer, and the Centennial Cross bluff, 320 feet up, −29°F and 13°F warmer.

The College Grandview District, on the bluff 200 feet above the flats, plans for −31°F and reads 9°F warmer. Fenelon Place, atop the Fenelon Place Elevator (sources put the climb at 168 to 189 feet), is bluff-top ground of the same kind, well above the flats. In Valley View the cold sits in the valley bottoms; the hillside point we checked, 150 feet up, plans for −32°F and reads 11°F warmer. The West End plans for −30°F, zone 4a, and reads 6°F warmer, while Barrington Lakes, southwest of town in a creek draw, plans for −31°F and reads 4°F colder.

The bluffs take the tender fruit: Lapins and Gold sweet cherries, Siberian C peach, Superior and Italian plums and Hardy Iowa apricot (−35°F). On the zone 4a ground, Contender peach (−30°F) fits; 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.

Asbury, Peosta, Epworth and the Catfish Creek uplands

West of town the bluffs give way to rolling upland drained by the forks of Catfish Creek. Asbury, on a bench 140 feet above its floor, plans for −29°F, MFTC zone 4a, typical winter −13°F, and reads 7°F warmer than downtown at bloom. Centralia, 250 feet up, plans for −30°F (4a) and reads 9°F warmer; Lore and Ballyclough, about 300 feet up, plan for −29°F and read 11°F to 12°F warmer.

Peosta, on a toe slope 70 feet up at 1,055 feet, plans for −32°F, typical winter −16°F, 1°F warmer at bloom, with its floor at −33°F and benches at −30°F. Epworth, on a bench, plans for −31°F and reads 3°F warmer. The creek bottoms are the cold spots: Twin Springs plans for −33°F and Kidder −32°F, both 3°F colder at bloom.

Asbury and Centralia can take the bluff list, Contender included. In Peosta and Epworth, plan on −32°F: Honeycrisp, Cortland and Macoun apples, Summercrisp and Ure pears on the slope, Toka plum and Lapins cherry. Iowa State doesn't recommend Honeycrisp or Cortland for home gardens because they need regular spraying; Freedom is the easier keeper.

Sageville, Balltown, Sherrill and the Little Maquoketa

North of Dubuque the Little Maquoketa runs out past Durango, which plans for −34°F on the river bottom and reads 5°F colder than downtown at bloom. Sageville, near river level, plans for −33°F over a −35°F floor. Rickardsville, 220 feet above its floor, plans for −29°F, MFTC zone 4a, and reads 12°F warmer, while O'Neill, in the hollow 1.8 miles north, plans for −34°F and reads 7°F colder. Sherrill plans for −30°F (4a) and reads 9°F warmer, Balltown, on the ridge 370 feet above its floor, −29°F and 12°F warmer, and Holy Cross, the highest town on the map, −30°F.

The ridge towns are apricot country: Westcot (−45°F), Sungold (−40°F) and Montana Mango (−35°F). Iowa State says Sungold and Moongold need each other, so plant two apricots; our pollination maps show what pollenizes what.

Galena, the Galena River canyon and Jo Daviess County

Galena sits on the Galena River, the old Fever River, in a substantial canyon that runs to the Mississippi a few miles southwest. The town point, at 620 feet at the canyon floor, plans for −31°F, MFTC zone 3b, typical winter −17°F, and reads 1°F colder than downtown Dubuque at bloom; the Galena Historic District plans for −32°F and reads 2°F colder. Within 3 miles the floor runs −32°F and the benches −29°F. That's about 2°F milder than Dubuque at the same height; the map follows the Galena station's own 30-year number (−31°F), from a short record. Elizabeth's station, just east, read −35°F in 1996 and 2019, so treat the canyon floor like Dubuque's flats.

The canyon carries cold to the river. Galena Junction and Portage, downstream, read 3°F to 4°F colder than downtown at bloom, and Bremen, 1.3 miles southeast in a side draw, plans for −28°F but reads 2°F colder. Climb out and it flips: Rice, 120 feet up, plans for −32°F and reads 6°F warmer, and Winston, 350 feet above its floor, reads 14°F warmer. In the 6,800-acre Galena Territory, type your address; it changes lot to lot.

East of town, Council Hill, on a bench 190 feet up, plans for −30°F and reads 6°F warmer, while Council Hill Station, on the floor 1.6 miles away, plans for −34°F, and Guilford's valley floor −34°F and 4°F colder. Rodden, toward Hanover, plans for −37°F, zone 3a, the coldest planning low of any named place on the map. Use the flats list in those bottoms; Winston, Rice, Council Hill and Galena's benches are the place for apricots, peaches and sweet cherries.

Bellevue, St. Donatus and the bluffs south of Dubuque

Bellevue sits on two levels of the Kingston Terrace (old river fill capped with windblown sand) in a valley between the North Bluff and the South Bluff, with Lock and Dam 12 at its river edge. The town point plans for −35°F, MFTC zone 3b, typical winter −16°F, 1°F warmer than downtown Dubuque at bloom. The floor within 3 miles runs −37°F and the benches −32°F, the biggest floor-to-bench step of any town on the map. NOAA's dam station read −34°F in 1996 and −35°F in 2009. Plant on the benches, and test drainage on the old Savanna Terrace along Duck Creek, where the Zwingle soils are poorly drained clay.

St. Donatus, on its valley floor at 667 feet, plans for −34°F, typical winter −18°F, 2°F colder at bloom, with benches at −30°F. La Motte, Bernard and Zwingle, on the upland but near their floors, plan for −33°F; Garry Owen, on a bench, −30°F (4a). Below the Mines of Spain, Massey, on the river, plans for −34°F; King, on the upland above it, plans for −28°F, MFTC zone 4a, and reads 14°F warmer at bloom.

On Bellevue's floor and in the St. Donatus bottoms, plant from the −40°F-and-colder list: Haralson, Frostbite and Spartan apples, Kerr and Centennial applecrabs (−50°F) and Evan's Bali. Ed Schultz, of Gallatin Gateway, Montana, saw zero winter injury on Centennial after a winter that hit −47°F.

Dickeyville, Hazel Green, Cuba City and the Wisconsin ridges

On the Wisconsin side the bluffs give way to rolling upland at 900 to 1,000 feet. Dickeyville, 260 feet above its floor, plans for −30°F, MFTC zone 3b, typical winter −15°F, and reads 10°F warmer than downtown at bloom, as does Sandy Hook. Louisburg, 3.8 miles south-southeast on its floor, plans for −33°F and reads 7°F colder. Sinsinawa plans for −30°F (4a), and Sinsinawa Mound above it −29°F and 13°F warmer.

East toward Hazel Green and Cuba City the valley floors run colder. Hazel Green, on a bench 150 feet up, plans for −30°F and reads 8°F warmer, over a −34°F floor. Cuba City, only 70 feet above its floor, plans for −33°F, typical winter −17°F, with the floor at −35°F. Etna, 2.7 miles east of Benton on a flat floor, plans for −36°F, zone 3a, and reads 7°F colder at bloom; Meekers Grove and Jenkinsville plan for −35°F.

The ridges take the bluff list (Contender is a good pick at Sinsinawa, worth a try at Dickeyville and Hazel Green); the Cuba City and Etna bottoms take the cold-bottom list. Upriver, the Prairie du Chien and Kickapoo map covers you.

Spring frost and bloom on the bluffs and flats

NOAA's 1991 to 2020 frost dates put the median last 32°F at April 14 at Lock and Dam 11, April 25 at Platteville, April 30 at the airport and at Bellevue's dam, and May 4 at Elizabeth. The last 28°F, about where open blossoms start dying, runs from April 2 at the Dubuque dam to April 24 at Elizabeth. In a late year (1 in 10) the last 32°F comes May 4 at the Dubuque dam and May 16 to May 21 elsewhere. The Weather Service's Dubuque records include 21°F on May 3, 2005.

On the spring layer the coldest named places are river flats and hollow floors: Frith Spur 9°F colder than downtown, East Dubuque, Louisburg, Etna and O'Neill 7°F colder. The warmest are high ground: Winston and King 14°F warmer, Sinsinawa Mound and Centennial Cross 13°F, Balltown and Rickardsville 12°F. 3°F to 4°F can separate no crop from a full one; in our own spring 2026 bloom frost in Montana, growers low in the valley got hit hard and those up on the benches fared much better.

In 2017 an early spring had Czipar's Orchard in Dubuque worried about a May frost in bloom; it never came, and the crop ran 1.5 to 2 weeks early. In 2024 Illinois Extension reported that Jo Daviess orchards around Galena and Elizabeth came through spring with little loss while orchards farther east lost fruit, and said Jo Daviess topography can protect orchards or cause problems.

Put apricots, peaches, plums and sweet cherries on your highest ground and apples, haskap and bush fruit lower: only about 15 percent of apple blossoms need to set, and open haskap flowers take 19°F, while grapes forgive less. Bob Purvis's rule: an east slope is ideal, and a north slope holds early bloomers back. Frost cloth at 0.5, 0.9 and 1.5 ounces per square yard gains about 4°F, 6°F and 8°F. Mow short through bloom, water a day or two ahead, and don't plant a hedge across the slope below your trees, since it dams the cold right where they stand.

What the weather records say

NOAA station records hold −37°F at Lock and Dam 11 and −35°F at Bellevue's Lock and Dam 12 (both January 17, 2009), −35°F at Cascade on the west edge (January 10, 1982) and at Elizabeth (February 3, 1996, and again in 2019), −32°F at Platteville (February 3, 1996) and −31°F at the Dubuque airport (January 31, 2019). The Galena station has 11 years on file with a low of −32°F in 2019; published tables for Galena list −35°F in February 1996. The Weather Service's Dubuque records include −32°F on January 7, 1887.

Downtown's typical winter of −16°F falls in USDA's 5a range (we haven't confirmed USDA's own 2023 zone for Dubuque). Our MFTC zone reads more than a full zone colder because USDA's is built on an average winter and ours on the bad night we plan for; at the median NOAA station the worst night in about 30 winters runs 13°F below the average yearly low.

What you can grow here

Bluff tops, ridges and benches, −28°F to −31°F. The South End, West End, College Grandview, Key West, Asbury, Centralia, Epworth, Sherrill, Balltown, Rickardsville, Galena's benches, Council Hill, King, Dickeyville, Hazel Green and Sinsinawa. Good picks: Honeycrisp, Haralson, Zestar!®, Freedom and Macoun apples; Summercrisp and Bartlett pears; Toka, Superior and Italian plums; Lapins and Gold sweet cherries; Evan's Bali and Meteor tart cherries; Westcot, Sungold and Hardy Iowa apricots; Siberian C, the hardiest peach we think is out there (very late ripening); and Marquette, Frontenac and La Crescent grapes. On the zone 4a spots, Contender peach, Rainier cherry (it cracks where it rains at ripening), Stanley plum, Liberty apple and D'Anjou pear (−30°F) fit; elsewhere in this band they're worth a try.

Town flats, valley floors and toe slopes, −32°F to −34°F. Downtown and the North End flats, East Dubuque, Galena's canyon floor, Peosta, Sageville, Cuba City, St. Donatus and Guilford. Good picks: Haralson, Honeycrisp, Wolf River and Spartan (−45°F), Zestar!®, Cortland and Golden Russet (−40°F) and Freedom apples; Kerr and Centennial applecrabs; Evan's Bali and Meteor tart cherries; honeyberry, Montana Black Currant, Red Lake currant, Invicta gooseberry and Boyne raspberry. Lapins, Gold, Superior and Siberian C (−35°F) clear these numbers, but they bloom early, so give them your highest corner. Liberty (−30°F), one of Iowa State's disease-resistant apples, is worth a try at −32°F.

Cold bottoms and hollows, −35°F to −37°F. Bellevue's floor, the Little Maquoketa mouth, Etna, Rodden, Meekers Grove and Jenkinsville. Stick with what has come through −40°F or colder: Norda and Mantet (−50°F), Frostbite and Haralson (−45°F) and Zestar!® (−40°F) apples; Kerr, Centennial and Chestnut applecrabs and Trailman (−60°F); Evan's Bali; honeyberry, the currants and Nanking Cherry. If you plant only one tree there, make it Kerr or Trailman.

Rootstocks, site and local troubles. Iowa State recommends EMLA 7 for a semi-dwarf apple and B.9 or G.41 for a dwarf, not M.26, which is very prone to fire blight. Where snow won't stay, mulch the roots. Plant on a 4 to 8 percent slope (Montana State's advice), off the hollow and the windswept crest. Ridgetop soils can be thin over bedrock and old terrace clays hold water, and Iowa State says wet soils kill fruit trees within a few years: dig a 2-foot hole, fill it twice, and if the second fill takes over 10 hours to drain, go elsewhere. Iowa State's list of main troubles: apple scab, cedar-apple rust, fire blight, codling moth and plum curculio. White trunk guards help young trees against sunscald. Taper water from mid-August so trees harden off.

Fruit history here

Native grapes thrived in the Upper Mississippi Valley in the late 1800s, and in 1919 Iowa had the sixth-largest grape crop in the country, until Prohibition, severe freezes, droughts and spray drift knocked it back. Hardy hybrids revived it, and in 2009 the Upper Mississippi River Valley became the largest American Viticultural Area, its petition crediting the bluffs and entrenched valleys with many microclimates. Joe and Katy Czipar started Czipar's Orchard along Highway 52 south of Dubuque in the early 1940s, and Dittmar Farms in Galena Country has farmed the same ground since 1854.

Questions people ask

What hardiness zone is Dubuque, Iowa?

Downtown Dubuque plans for −33°F, MFTC zone 3b, with a typical winter of −16°F. The South End and West End plan for −30°F (zone 4a) and the river flats −34°F. NOAA's average yearly low, −17°F on the river and −18°F at the airport, sits in USDA's 5a range; USDA's zone is based on an average winter, ours on the bad night we plan for.

When is the last frost in Dubuque?

NOAA station records for 1991 to 2020 put the median last 32°F at April 30 at the airport and April 14 at Lock and Dam 11 on the river. In a late year (1 in 10) it comes May 16 at the airport and May 4 at the dam.

Does the Mississippi River keep Dubuque warmer?

In spring and fall the river station at Lock and Dam 11 does better, with 190 frost-free days against 163 at the airport. On the coldest winter nights it's the other way around: in the January 2009 cold snap the dam read −37°F and the airport −30°F.

Can you grow peaches in Dubuque?

Iowa State says peaches aren't reliably hardy in northern and central Iowa. Siberian C (−35°F) clears the planning low in every Dubuque neighborhood we checked, and Contender (−30°F) fits the zone 4a bluffs and Asbury. Peaches bloom early, so plant them high on the bluff, and count on the tree before the crop.

Where are the frost pockets around Galena?

Low ground in the canyon and the creek floors. On a still bloom night the Galena Historic District reads 2°F colder than downtown Dubuque, Galena Junction and Portage 3°F to 4°F colder, and Guilford 4°F colder. The high ground south of town is the opposite: Rice reads 6°F warmer and Winston 14°F warmer.

What fruit grows in the Driftless Area around Dubuque and Galena?

Half the growing ground here plans for −31°F to −33°F, MFTC zone 3b, so Honeycrisp, Haralson and Zestar!® apples, Toka and Superior plums, Lapins sweet cherry, haskap, currants and Marquette grapes all fit. The zone 4a bluffs add Contender peach and Rainier cherry.

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.