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Saint pépin

Overview

A white, interspecific hybrid from the Upper Midwest, Saint‑Pépin (often written St. Pepin) shows up in Wisconsin and Iowa farm newsletters, Quebec SAQ shelves, and a handful of New York AVAs—quietly doing the work of a northern white that can take a winter. Breeder and nursery summaries agree it’s a cold‑hardy, early‑ to mid‑ripening white used for dry, sparkling, and even ice wine; growers also emphasize that the variety is pistillate (female) and needs a nearby pollinizer at bloom. As the University of Minnesota’s fruit update reminded growers in June 2025, “most cold climate grapes have perfect flowers… A variety that does not…is St. Pepin…which requires nearby cultivars to act as pollinizers.” (amberggrapevines.com)

Origin & Breeding

Wisconsin farmer‑breeder Elmer Swenson created St. Pepin (selection ES 282). The ibiblio Swenson archive lists the parentage as ES 114 (itself Minnesota 78 × Seibel 1000 “Rosette”) crossed with Seyval; it also records St. Pepin’s pistillate flower type. Wein.plus adds that its family tree pulls genes from labrusca, lincecumii, riparia, rupestris, and vinifera. Release timing is recounted differently: Double A Vineyards lists “Year Released: 1983,” while English‑language references often say 1986; even the crossing year floats—from 1950 (wein.plus) to 1971 (German Wikipedia). Those contradictions are part of the grape’s lore in the North. (ibiblio.org)

St. Pepin also sits in the background of newer cold‑climate stars: Iowa State’s Midwest Grape & Wine Industry Institute notes La Crescent’s pedigree as “St Pepin × [Swenson] 6‑8‑25.” (extension.iastate.edu)

Climate Adaptation & Hardiness

How cold is “cold‑hardy” for St. Pepin? Sources disagree—and growers seem to embrace the ambiguity:

  • “At least −25°F” when properly hardened, say multiple varietal summaries. That’s about −32°C. (en.wikipedia.org)
  • An Iowa winery’s field page offers a more conservative range—hardy to −15° to −20°F—yet cites “predicted temperature of 50% primary bud kill: −32°F” and “no apparent injury to the trunk.” (tasselridge.com)
  • A New Brunswick nursery sells it as a Zone 3b option for Eastern Canada, while a U.S. nursery ships it widely as suitable for Zones 4–8. (cornhillnursery.com)

In winter 2024–25, the UW Fruit Program noted reports of unexpected dieback in hybrids including St. Pepin, speculating about root injury linked to low snow cover—another reminder that “hardiness” is as much site and season as it is genetics. (fruit.wisc.edu)

Phenology

  • Budbreak: “Mid‑season (with Concord),” according to nursery guidance. (doubleavineyards.com)
  • Bloom and pollination: Tassel Ridge in Iowa calls St. Pepin “hard to grow because it is pistillate,” and they interplant LaCrosse and Brianna “because they bloom at about the same time.” (tasselridge.com)
  • Ripening/Harvest: Double A lists “Early Season,” while Amberg calls it “early to mid ripening.” In Quebec, Léon Courville’s sparkling label remarks that St‑Pépin is “the first grape to be harvested in the autumn” for their méthode champenoise base. Iowa State’s 2024 berry‑composition snapshots show 21–22.3° Brix and pH ~3.3–3.4 by late August to early September in central and north‑central Iowa. And at Wollersheim (Lake Wisconsin AVA), grapes for ice wine remain on the vine until mid‑December, reaching 33–36° Brix before the frozen pick. (doubleavineyards.com)

If you’re looking for a tidy calendar—there isn’t one. What emerges from the records is a grape that can be first off the press for sparkling in Quebec, mid‑season for dry whites in Wisconsin, and last of the year as ice wine on the same slopes. (olalavert.com)

Growth Habit

Vigor is not in dispute—most describe St. Pepin as vigorous. Training, however, is a choose‑your‑own‑adventure:

  • One nursery lists the growth habit as “upright” and recommends Top Wire Cordon (high wire). Another grower in Michigan is converting rows to Geneva Double Curtain to “give them more room to grow.” A Swenson‑era grower guide suggests cane pruning, and a SARE on‑farm trial in the Northeast found both Top Wire Cordon and modified GDC “very acceptable” for St. Pepin. (doubleavineyards.com)

Those choices look pragmatic: where the vine wants to drape, growers split the canopy (GDC); where labor is tight, high‑wire cordon reduces in‑season shoot work. (projects.sare.org)

Disease & Physiological Issues

  • Powdery mildew: A multi‑year Northeast trial ranked St. Pepin among cultivars with high powdery mildew incidence in at least one of the two years monitored. Double A likewise flags it as “highly susceptible.” (mdpi.com)
  • Downy mildew: Nurseries and extension updates repeatedly connect St. Pepin with late‑season downy mildew pressure. Iowa State’s 2025 Week 4 report even called DM “typically expected on…La Crosse, and St. Pepin,” while a 2024 Wisconsin update documented DM resurgence late in harvest. (amberggrapevines.com)
  • Botrytis/bunch rots: Several nursery sheets list Botrytis susceptibility; Wisconsin and Midwest spray guides emphasize pre‑/post‑bloom coverage where bunch rots are a risk. (amberggrapevines.com)
  • Physiology and fruit set: The pistillate flower is central to St. Pepin’s personality. Lon Rombough’s grower note cautions that “productivity is dependent on good pollination… the number of clusters per vine may be low,” and recommends one LaCrosse for every three St. Pepin vines to ensure pollen and—even handily—a blending partner. (bunchgrapes.com)

Fruit Composition & Sensory Profile

  • Numbers from the field: In the 2024 Iowa snapshots, St. Pepin samples moved from ~17–19° Brix in mid‑August to ~21–22° Brix by early September, with pH trending from ~3.1 to ~3.4 and TA easing from the mid‑teens (g/L as tartaric) down toward ~8–10 g/L as harvest approached. (extension.iastate.edu)
  • What growers taste: Cedar Creek/Wollersheim describe their estate St. Pepin as dry with “mineral…chalky soil and stone fruits,” fermented cool, then ML and seven months in French oak. In eastern Canada, Labranche’s cuvée (85% St‑Pépin) leans to Golden apple, pineapple, honey, and white flowers; Coteau Rougemont’s 100% Saint‑Pépin talks preserved lemon, peach jam, and a fresh, mineral attack; small Midwestern labels often lean to apple/pear, sometimes with a honeyed finish when bottled semi‑sweet. One nursery sheet mentions “Muscat‑like floral” and even “a hint of foxiness,” while an Iowa winery’s vineyard page calls it “very fruity…German‑style” and notes typical sugars 17.6–21.0° Brix. The spread feels like the grape’s calling card. (cedarcreekwinery.com)

Winemaking Approaches

Producers use St. Pepin where their site and style intersect:

  • Barrel‑fermented/ML dry whites: Wollersheim moved St. Pepin into a Chardonnay‑like lane—cool ferment, malolactic, batonnage, seven months in French oak. “We wanted to make it in a Chardonnay style,” their winemaker noted when the wine debuted in 2022. (wollersheim.com)
  • Traditional‑method sparkling: Léon Courville’s Muse Brut is 100% St‑Pépin, with primary and malolactic in tank, then 15 months on lees in bottle; the estate calls St‑Pépin its first harvest fruit, which helps for low‑alcohol, high‑acid base wines. (olalavert.com)
  • Ice wine: In Lake Wisconsin, St. Pepin hangs to mid‑December for 33–36° Brix; the frozen pick is pressed and slowly fermented into a dense, honeyed dessert wine. Door Peninsula Winery on the Ledge has also bottled a St. Pepin ice wine. (wollersheim.com)

Regional enology teams still talk generally about cold‑hardy whites pushing high acidity and the need for deacidification and careful yeast choices; St. Pepin, by contrast, sometimes comes in balanced enough to permit ML and oak without surgery—on some sites, in some years. (portal.nifa.usda.gov)

Example Styles & Uses

  • Wisconsin dry, oak‑aged: Cedar Creek/Wollersheim’s estate St. Pepin (2025 Finger Lakes Intl. silver) shows the “mineral/stone fruit” house style with ML and batonnage. (cedarcreekwinery.com)
  • Quebec still whites: Coteau Rougemont bottles 100% Saint‑Pépin; Labranche’s Signature St‑Pépin uses French oak and positions it for Chardonnay lovers; Pigeon Hill’s 2024 St‑Pépin is a dry, mineral monocépage. (coteaurougemont.ca)
  • Traditional‑method sparkling: Léon Courville’s Muse Brut St‑Pépin (IGP Vins du Québec). (olalavert.com)
  • Semi‑sweet and sweet: Orchard Country’s 7% RS St. Pepin leans honeyed; small Midwest labels describe apple‑pear profiles. (orchardcountry.com)
  • Ice wine: Wollersheim Ice Wine (100% St. Pepin) is a long‑running program; Door Peninsula’s Frostline (St. Pepin) adds another Wisconsin example. (wollersheim.com)

Tassel Ridge, after years of blending, finally released a varietal in 2019: “Some people will say it resembles an off‑dry Riesling,” they wrote, tying the flavor back to their Mahaska County sites—and to the logistical reality of planting pollinizers in alternating rows. (tasselridge.com)

Open Questions & Conflicting Reports

  • How hardy is it, really? The same grape is sold for Zone 3b in New Brunswick, pegged at −25°F in varietal notes, described as hardy only to −15/−20°F by one Iowa winery—yet with a modeled 50% bud kill at −32°F. Different rootstocks? Acclimation? Site? All of the above, perhaps. (cornhillnursery.com)
  • Upright or trailing? Some nurseries call St. Pepin “upright” and pitch Top Wire; others show growers migrating to Geneva Double Curtain. A SARE trial liked both TWC and mod‑GDC, giving a slight yield edge to mod‑GDC in one season’s data. (doubleavineyards.com)
  • Acid and style: One nursery sheet says “low acidity,” yet Iowa numbers routinely show TA in the 8–14 g/L range as the fruit moves from August into early September. Meanwhile, producers span dry oak‑aged, traditional‑method sparkling, and very sweet ice wine. Maybe “low acidity” is, like “hardy,” a moving target tied to year and crop load. (amberggrapevines.com)
  • Disease expectations: Extension writers now “expect” late‑season downy mildew on cultivars including St. Pepin, but a Northeast trial saw no DM in its seasons while rating St. Pepin as among the higher powdery‑mildew‑incidence cultivars in one year. Vintage and canopy management seem to write this chapter anew each season. (extension.iastate.edu)
  • Pollination logistics: Rombough recommends one LaCrosse for three St. Pepin; Tassel Ridge alternates rows with LaCrosse and Brianna. Both stress bloom synchrony. How much does pollen source—and wind and row spacing—shape yields and cluster count year to year? (bunchgrapes.com)

References

  • UMN Extension, Fruit update: bloom and pollination note on St. Pepin (June 12, 2025). https://blog-fruit-vegetable-ipm.extension.umn.edu/2025/06/fruit-update-june-12-2025.html (blog-fruit-vegetable-ipm.extension.umn.edu)
  • Grapebreeders (ibiblio): Elmer Swenson parentage table (ES 282 St. Pepin = ES 114 × Seyval). https://www.ibiblio.org/grapebreeders/slarsen/Grapebreeders/ES_parent.htm (ibiblio.org)
  • wein.plus lexicon: parentage and species background. https://glossary.wein.plus/st-pepin (glossary.wein.plus)
  • Double A Vineyards: St. Pepin page (release year, budbreak, training, disease susceptibility). https://doubleavineyards.com/products/st-pepin-grapevine-standard (doubleavineyards.com)
  • Amberg Grapevines: St. Pepin nursery sheet (ripening window, disease notes). https://www.amberggrapevines.com/varieties/st-pepin (amberggrapevines.com)
  • Wikipedia (EN/DE): capsule histories (release dates, crossing date variants, hardiness claim). https://en.wikipedia.org/wiki/St.Pepin(grape) and https://de.wikipedia.org/wiki/St.Pepin(Rebsorte) (en.wikipedia.org)
  • Iowa State University Extension: Midwest Wine Grape Berry Composition Reports (2024 Weeks 3–5) with St. Pepin Brix/pH/TA tables. https://www.extension.iastate.edu/commercialhort/midwest-wine-grape-berry-composition-report-2024-week-3 and Week 4 and Week 5 pages (extension.iastate.edu)
  • Iowa State Yard & Garden: “What are some good grape varieties for Iowa?” (St. Pepin profile: season, growth, disease, pistillate/pollenizer). https://yardandgarden.extension.iastate.edu/faq/what-are-some-good-grape-varieties-iowa (yardandgarden.extension.iastate.edu)
  • Tassel Ridge Winery: pollination logistics and 2019 varietal note. https://tasselridge.com/2019-iowa-st-pepin-is-now-available-at-tassel-ridge-winery/ and vineyard facts page. https://tasselridge.com/tassel-ridge-winery/vineyard-facts/ (tasselridge.com)
  • Corn Hill Nursery (NB, Canada): St. Pepin listing (Zone 3b, pollinator required). https://www.cornhillnursery.com/online-store/p/st-pepin (cornhillnursery.com)
  • Honeyflow Farm (MI): grower note on switching St. Pepin rows to GDC. https://honeyflowfarm.com/index.php/vineyard/white-wine-grapes/st-pepin (honeyflowfarm.com)
  • Rombough, Lon (bunchgrapes.com): St. Pepin grower notes (pistillate, pollination strategy, cane pruning, −20 to −25°F). https://www.bunchgrapes.com/st-pepin_grapes.html (bunchgrapes.com)
  • Horticulturae (MDPI): Disease susceptibility of interspecific cold‑hardy cultivars (powdery mildew incidence including St. Pepin). https://www.mdpi.com/2311-7524/7/8/216 (mdpi.com)
  • ISU Extension: Midwest Fruit Pest Management Guide (and 2025 addendum); UW/ISU articles referencing late‑season DM. https://edustore.purdue.edu/id-465-w.html and https://www.extension.iastate.edu/viticulture/midwest-fruit-pest-management-guide and WI updates. https://fruit.wisc.edu/2024/08/26/wisconsin-vineyard-update-august-2024-late-season-downy-mildew/ (edustore.purdue.edu)
  • UW Fruit Program (2025): note on unusual dieback in hybrids incl. St. Pepin (root injury speculation). https://fruit.wisc.edu/2025/06/05/note-to-grape-growers-unusual-vine-dieback-observed-this-spring/ (fruit.wisc.edu)
  • La Crescent profile (MGWII): pedigree citing St. Pepin parentage. https://www.extension.iastate.edu/wine/grape-variety-la-crescent/ (extension.iastate.edu)
  • Léon Courville Vigneron: Réserve St‑Pépin (still); Muse – St‑Pépin Brut (sparkling details). https://www.leoncourville.com/wines/reserve-st-pepin and product page via retailer with méthode champenoise details. https://www.olalavert.com/products/cou5916-muse-st-pepin-brut (leoncourville.com)
  • Coteau Rougemont: Saint‑Pépin (100%). https://www.coteaurougemont.ca/products/saint-pepin (EN mirror available). (coteaurougemont.ca)
  • Domaine Labranche: Cuvée St‑Pépin (blend with Vidal/Frontenac blanc; oak; tasting). https://www.labranche.ca/en/products/white-wine-cuvee-st-pepin/ (labranche.ca)
  • Vignoble Pigeon Hill: Le Saint‑Pépin 2024 (dry, mineral monocépage). https://lesminettes.ca/products/le-saint-pepin-2024 (lesminettes.ca)
  • Orchard Country (Door County, WI): St. Pepin semi‑sweet (7% RS). https://www.orchardcountry.com/products/st-pepin (orchardcountry.com)
  • Door Peninsula Winery: Frostline ice wine (St. Pepin). https://store.dcwine.com/winery/product/frostline/ (store.dcwine.com)
  • Wollersheim Winery: St. Pepin (dry, ML, oak); “A New Wollersheim Wine…” blog; Ice Wine (100% St. Pepin). https://www.wollersheim.com/product/st-pepin/; https://www.wollersheim.com/a-new-wollersheim-wine-has-arrived-st-pepin/; https://www.wollersheim.com/product/ice-wine/ (wollersheim.com)
  • Lake Wisconsin AVA page listing St. Pepin as a local cultivar. https://en.wikipedia.org/wiki/Lake_Wisconsin_AVA (en.wikipedia.org)

If you want additional grower voices from Ontario, the Upper Hudson, or the Maritimes, I can expand this with interviews and field notes from those regions—St. Pepin has a way of changing its story when you cross a river or a border.