A Passion
for Discovery
David Zlesak fell in
love with rose breeding
as a boy, and his
passion has never
waned.
IN JUNE, IF YOU ARE LOOKING FOR
DAVID ZLESAK, you’ll likely find him sitting on a beat-up cooler in his Edina trial
garden, his blue eyes shaded by a widebrimmed hat as he happily hand-pollinates roses—often for hours at a time. An
associate professor of horticulture at the
University of Wisconsin-River Falls, David
has been breeding hardy landscape roses
for 30 years. Many of them have won certificates in the American Rose Society’s
American Rose Center trials. And, in the
last few years, an increasing number of
his hybrids have been released by nurseries, including Proven Winners’ Oso
Happy® series of roses and First Editions®
Above and Beyond™ (Rosa
‘ZLEEltonStrack’), a sizeable, cane-hardy
rose with apricot-colored blooms introduced by Bailey Nurseries last year.
Seeing his roses—and other plants—
make it to market after what often
amounts to more than a decade of work
for each release has been exciting and
gratifying. But what really motivates
David, who earned graduate degrees in
plant breeding and genetics at the
University of Minnesota, is his infectious
passion for discovery, learning, plants and
people. “When I was young, I thought the
whole process of having a plant go to
market would feel magical,” he says. “But
I’ve learned that factors beyond my control influence choices that are made about
what nurseries want, and I’m OK with
that because I love what I do and I get
great satisfaction from learning about
plants and from the friendships that I’ve
developed with other plant breeders.”
Lanky and soft-spoken with long dark
hair, most often pulled back into a lowslung ponytail, David looks more like a
poet or painter than a researcher known
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MARY LAHR SCHIER
By Meleah Maynard
David is constantly experimenting
with plants. This ageratum was
never introduced to market.
MELEAH MAYNARD
hardy, and that’s a value
his dad, David visited Strack nearly every
week for years and eventually came to
understand his mentor’s appreciation for
hardy species hybrids over showier
repeat-bloomers that often could not
make it through the winter. And so began
David’s research into crossing hardy
species roses with desirable, but tender,
cultivars in hopes of creating a winning
combination.
to me and others in
One Special Seedling
My niche is developing
plants that are extra
our climate.
—David Zlesak
By the time he was 13, David was
already starting to breed roses “because I
thought it would be fun,” he says, explaining that his interest was inspired by an
article he read about rose-breeding hobbyist Will Radler in the Milwaukee Journal.
David wrote to Radler, who would later be
known for developing the Knock Out®
series of shrub roses, and Radler wrote
back. He also connected his young fan
with Elton Strack, a hobby rose breeder
who lived just a few miles from David.
Strack became both a mentor and “like a
grandfather,” David says. Dropped off by
Marketing often drives a plant’s trade
name, but breeders have more freedom to
choose a new introduction’s variety name.
In the case of his most recently released
rose, Above and Beyond, David chose Rosa
‘ZLEEltonStrack’, a combination of the
customary first three letters of the breeder’s name and the full name of his mentor
and friend, with whom he continued to
correspond and visit even after going to
college.
David says that of all the roses he’s
grown in 30 years of rose breeding, Above
and Beyond is his favorite. Reliably hardy
to USDA Zone 3, Above and Beyond is a
climbing rose that can also grow into a
shrub as large as 10 to 14 feet tall and
wide. Its apricot-colored, semi-double
flowers open early in mid- to late
spring—before the arrival of Japanese
MELEAH MAYNARD
At his Edina trial garden, David harvests rose hips for future breeding.
David carefully pollinates a rose.
MELEAH MAYNARD
for his work in plant propagation, pathology and genetics. But while there is an
unmistakably artistic quality to the way
he talks about and experiences the world
around him, David is the sort of person
who, even as a boy, was driven and serious-minded enough to know that he
either wanted to be a horticulturist or a
math teacher. “And then I took calculus in
college and decided, ‘Nope. I’m going with
horticulture,’ ” he recalls, laughing.
Looking back, it seems he was destined
to follow that path. Growing up in
Milwaukee, Wis., David looked forward to
visiting his grandparents’ 5-acre farm, a
half-day’s drive away, where he remembers helping his grandma in her gardens
and going for walks in the woods with his
grandpa. Soon, he began saving his
money until springtime and asking his
parents to drive him to distant nurseries
so he could buy plants to grow at home.
“They didn’t share my interest in plants,
but they weren’t discouraging,” David
recalls, adding that even a foot fracture
didn’t stop him from making his parents
keep their promise to take him to Jung’s
Garden Center’s main location in
Randolph, Wis., when he was 12.
Rose hips marked and ready to head to the lab.
May/June 2016
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First Editions® Above and Beyond™ rose
PHOTOS COURTESY OF WALTERS GARDENS
beetles—and the plants are very resistant
to fungal disease. The rose is a descendent of a Rosa virginiana plant that Strack
collected from Canada and planted in his
own garden.
David made the cross that produced
Above and Beyond in 2000, combining a
non-hardy yellow miniature with a hybrid
of Strack’s rose in hopes of eventually
breeding a rose with warm-hued blooms
that offered hardiness and repeat bloom.
To his surprise, he succeeded with a firstgeneration hybrid even though it usually
takes multiple generations to produce a
desirable seedling. “It was so unexpected,”
he says. “I thought I would get warm
undertones with maybe a lot of pink on a
plant that was somewhat small in size,
and instead I got this huge monster plant
with apricot blooms. All you need is that
one special seedling.”
But that is no easy feat. Though
Strack dreamed of breeding a rose
that would be introduced to
the market, he died before
achieving his goal. David
had already been breeding
roses, primarily, but also
ageratum, heliopsis and
ninebark, for 20 years when
his first breeding success,
Tuscan Sun heliopsis (Heliopsis
helianthoides ‘Tuscan Sun’
PP18763), was introduced by Proven
Winners® in 2006. Oso Happy® Candy
Oh! followed in 2008, the hard-earned
result of a selection process that began in
Rhinelander, Wis., (zone 3) where its
mother was selected for its strong hardiness and distinctive color.
Next came Little Devil™ ninebark,
which won the 2011 American Nursery
Landscape Association’s Garden Idol
Award for best plant of the year. Then the
rest of the Oso Happy® series, which
includes the diminutive, thornless rose
Oso Happy™ Smoothie, to which David
gave the botanical name Rosa
‘ZLECharlie’ PP23456. “For my dad,
PHOTO COURTESY OF BAILEY NURSERIES
A Passion for Discovery
Above and inset: Heliopsis helianthoides ‘Tuscan Sun’
Charlie, who sounds prickly, but when
you get up close, he’s pretty much thornless,” David jokes. To Oso Happy™ Petite
Pink, a hard, floriferous miniature that
David started working on in the late
1990s, he gave the cultivar name Rosa
‘ZLEMarianneYoshida’ PP22,205, in
honor of his close friend and landlady
since 1999. “She’s always been so good to
me and let me have my growing racks and
lights on in the basement,” David says.
Putting a Priority on Hardiness
Located at the bottom of a hill on a
frontage road off Highway 62, David’s
Edina trial garden is packed with roses,
and a handful of other plants he’s working on every season. He moved his plants
there in 2008 after the garden plots he
rented were repurposed and a friend, who
owns an adjacent house, offered to let
him turn the space into a garden. From
the road, the oddly shaped parcel of flowers interspersed with a few mulch-covered
paths might pass for a park. But down on
the ground, it’s clearly an outdoor lab.
Everywhere you look, small paper tags
dipped in polyurethane to protect them
from the elements, hang from thin
strings tied around rose stems. Some
plants have just a few tags while others
have huge clusters that flap in the wind.
Some have understandable names on
them, but most tags just have letters and
numbers that David records to indicate
the source of the pollen he used to make a
cross—aka the daddy of the plant to be.
After years of striving for crosses that
produce traits like a particular flower
color, repeat bloom, a tidy branching
structure and disease resistance, David
has decided he needs to take a step back.
“I realize I’ve watered down the hardiness
of plants to get other traits that I want,
so I want to go back to focusing on developing plants that do well in our region,”
he explains. “My niche is developing
plants that are extra hardy, and that’s a
value to me and others in our climate.”
His goal is to produce a hardy red climbing rose, similar to Above and Beyond.
That plan dovetails nicely with David’s
role as coordinator of the Northern
Earth-Kind® Rose Trials, which are part of
the larger Earth-Kind program launched
by scientists at Texas A&M University in
the early 1990s. Like the original program, which seeks to provide the public
with reliable, regionally appropriate information on sustainable growing practices
and varieties of plants, the Northern
Earth-Kind Rose Trials aim to identify
consistently beautiful, hardy, pest- and
disease-resistant landscape roses for the
northern Midwest region.
David and several colleagues started the
trials in 2007. Last year, his unflagging
leadership was recognized when he and
others on the National Earth-Kind Rose
Team received the Texas A&M AgriLife
Vice Chancellors Award in Excellence for
Collaboration. After much discussion with
Meleah Maynard is a Minneapolis-based
writer and editor. She blogs at everydaygardener.com.
PHOTO COURTESY OF DAVID ZLESAK
PHOTO COURTESY OF BAILEY NURSERIES
David’s introductions include Little Devil™ ninebark, a petite form of ninebark.
northern rose growers, 20 roses were
selected and planted in trial sites across
Minnesota, Iowa, Colorado and Nebraska.
Throughout the years of the trials, David
has received new shrub rose introductions
from nurseries that he and his collaborators have been studying.
Results of the trials will soon be published, and the Northern Earth-Kind®
roses will also be designated. “I love being
part of the Earth-Kind team,” David says,
explaining that he’s proud that his volunteer team of collaborators has been able
to conduct real-world, scientifically sound
experiments to identify plants and practices that help people develop not only
beautiful but environmentally responsible
landscapes.
“Waking up, no matter the time of year,
I look forward to every day,” he says.
“There are projects in the garden and the
lab, and there are always opportunities to
learn from and work with other plant
lovers. But I think my greatest impact on
horticulture will be serving as an effective
mentor to my students, helping spark and
fuel their passion for plants and explore
and find their own niche.”
Oso Happy™ Petite Pink rose
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