Cold-hardy research in bloom

The story goes that in 1860, famous journalist Horace Greeley said, "I would not live in Minnesota, because you cannot grow apples there." Fast forward more than a century and a half and one of the most popular apple varieties in the United States—one widely enjoyed around the world—was created right here in Minnesota. The Honeycrisp was even named Minnesota’s official state fruit in 2006, as if to say, “How do you like them apples, Mr. Greeley?” Released in 1991 by the University of Minnesota’s renowned cold-hardy breeding program, Minnesota’s crispiest of retorts to Greeley took just 131 years to come to fruition (though the University’s first apple introduction came in 1920). 

Quality, of course, takes time. 

The unique challenges of Minnesota’s cold winters have long frustrated seasonally optimistic gardeners, farmers, and other growers of fruits, vegetables, flowers, and more. 

Still, since the University of Minnesota Department of Horticultural Science’s founding in 1888, the program has not sat idly by, having so far bred more than 400 varieties of cold-hardy adaptations. About 100 of these have been fruit varieties, with roughly 30 of those apples. Other fruit introductions include grapes, apricots, cherries, raspberries, blueberries, strawberries, and even kiwi berries. And just this year the trees that produce the University of Minnesota’s newest pear, known as Juicy Jewel™, became available for purchase. 

But what of the other 300 cold-hardy introductions?

So far as history has documented, no famous person has ever been quoted as saying they would not live in Minnesota because you cannot grow azaleas here, or say, chrysanthemums (‘mums’ for short). But were it not for the University of Minnesota’s cold-hardy breeding program, living in Minnesota would be a lot less colorful, that’s for certain. 

And in any case, according to Assistant Professor Seth Wannemuehler, who was recently named head of the Woody Ornamental Plant Breeding & Genetics program, “The public demands beautiful flowering shrubs.”

Meeting demand

Among those beautiful flowering shrubs are azaleas, and the University of Minnesota has been particularly successful in bringing the full bouquet of colors to the clamoring Minnesota masses, introducing 14 highly successful azalea varieties.

“There wasn't anything like cold-hardy azaleas in the north back in the 1950s,” says Wannemuehler. “We have some native ones here and there, but they don't quite put on the show that Minnesotans wanted. We didn’t have big, beautiful, colorful plants.”

The big players in the horticulture industry, Wannemuehler says, are based in climates that are warmer—Georgia down south, or Oregon in the west, for example. 

“And they breed plants that do well in those environments,” says Wannemuehler. “Unfortunately, here in Minnesota, where we can routinely get down to -30F, those plants don't necessarily survive.”

And so researchers experiment, crossing a plant with one desirable quality and then another until they get the characteristics they’re looking for—the characteristics that Minnesotans, midwesterners, and even Canadians demand. 

This process—which often takes 15 years from start to finish for one introduction (“Unfortunately, all woody plants just are slow,” laments Wannemuehler. “It's not an overnight thing—I wish it were”)—takes place at dozens of climate-controlled greenhouses and 145 growth chambers on the Twin Cities campus in St. Paul, outdoors at the North Central Research and Outreach Center in Grand Rapids (the northernmost land-grant horticultural research center in the continental U.S. and a critical USDA Zone 3 cold-hardiness testing site), and at the University of Minnesota Landscape Arboretum, ensuring that whatever is bred survives within Minnesota’s borders.

In fact, the Horticultural Research Center adjacent to the University’s Minnesota Landscape Arboretum (a Minnesota gem) has emerged as the center of fruit research and woody landscape plant breeding for the Upper Midwest. The 230-acre site serves as the research arm of the University of Minnesota College of Food, Agricultural and Natural Resource Sciences’ Department of Horticultural Science, and is part of a network of 10 Research and Outreach Centers maintained by the university around the state.

But back to azaleas. 

“The ‘Light series’ is a good example of breeding for cold hardiness and something that we never had up here in the northland,” says Wannemuehler. “We brought in a lot of colors. I mean, if you've ever been to the arboretum in the spring, we've got pinks, electric light double-pinks, we've got oranges, we’ve got yellows, whites, and reds now.”

These azaleas—common in zone 4 landscapes today but unknown as recently as the ’80s—are world-renowned for cold-tolerance and color—an achievement that took two decades. 

“We made a new market, essentially, and got nursery growers involved and the public,” says Wannemuehler. “We're meeting the demand of both the consumer and the seller.”

Marvelous, cold-hardy mums

If you’re not yet impressed with the University of Minnesota’s work with everything from azaleas to apples, consider your grandmother’s favorite plant: chrysanthemums. 

“Go anywhere in the world—to any retailer selling garden chrysanthemums in the world—and the particular plant phenotype you’ll see was developed here at the University,” says Neil Anderson, professor of flower breeding and genetics. “They all have that hemispherical shape.”

Anderson is referring to the style of chrysanthemums known as “cushion-habit,” a genetic discovery University of Minnesota mum breeders patented in 1977 as ‘Minngopher.’ In total, the cold-hardy research program is responsible for more than 90 chrysanthemum introductions over the past 100 years. Other introductions nod to the University of Minnesota or the State of Minnesota in their names, including the ‘Maroon Pride’, ‘Duluth’, ‘Snowsota’, and ‘Lemonsota’ varieties. 

People might be surprised to learn that not only is the University of Minnesota’s program the oldest public breeding sector of chrysanthemum in the world—it is the only public sector chrysanthemum breeding program in the United States.

“When the Department of Horticulture was founded, flowers and floriculture were paramount,” says Anderson. “They were meant to enhance the lives of Minnesotans.” 

“A lot of land-grant universities had flower breeding programs, many of which were chrysanthemums. But over time, they disappeared,” he adds. “Minnesota maintained our program mainly because of the critical work that we've done with winter hardiness and cold tolerance, as well as the development of the garden chrysanthemum crop itself.” 

For Minnesotans, who don’t like to brag, mum is often the word. But where would cold-climate states be without this work? 

“If you grow them outdoors, in your yard or something, they'd be green all year. They'll never develop flowers or bloom for you at all. Without the Minnesota work, there'd be a lot of things lacking in color in the fall landscape.”

Why flowers matter

Maybe the million dollar question is why any of this matters. The answer varies. 

For one, Minnesota’s landscape and nursery industry is today worth around $3.5 billion annually and includes more than 40,000 employees across 2,000 companies—largely family-owned businesses. 

But the second part of the answer is more nuanced and harder to measure. 

Anderson, who graduated from the University in 1985 (MS), 1989 (PhD) and returned as a professor in 1999, has dedicated much of his life to this endeavor. Along with Wannemuehler and countless other researchers over the past century-plus, they’ve been growing far more than plants. Dozens of undergraduate, graduate, and PhD students also work alongside University of Minnesota horticulture researchers each year to learn about plant breeding and genetics and gain valuable research experience.

For Anderson, the answer to why this matters is that growing flowers is ultimately about more than growing flowers.

“It's the discovery of the unknown, because most everything we work with, we don't know much of anything about the crops, and so it's always great to lay the foundational research and create things that are new and beautiful. It excites me too, to work with students and get them all excited as the next generation of professionals to create new things, to problem solve … to let their brilliance take over and transform the landscape.”

But let’s not forget the bottom line: Meeting the needs of the public has always been the mission of Minnesota’s one and only public land-grant university.

Make a gift to the Woody Landscape Plant Breeding Research fund and/or the Fruit Breeding and Genetics fund. You can also support flower breeding research by purchasing University of Minnesota varieties from nurseries that are members of the nonprofit Minnesota Nursery Research Corporation.