What a great day for torturing roses!

It's sunny and warm, sky's fluffy with clouds, and we're walking the 10-acre field in Chester County known as "rose hell."

Really, that's what they call it, because this is where several thousand roses are set in the ground and left alone to see which ones can take the heat — and humidity, drought, wind, frost, snow, fungus, bugs, and all else. At the end of three or four years, minimum, whatever's still standing has a shot at becoming the next big star of the rose world.

They have to survive with no irrigation, no sprays for insects or disease, no protection from extreme temperatures and conditions, no fertilizer, no pruning. Nothing, because, believe it or not, these trials are meant to simulate conditions in the average American garden — and we're pretty awful to our plants.

"If it was possible to get written up for rose abuse, we would be. They have a nasty, brutish, and short life here," says Steve Hutton, president and CEO of the Conard-Pyle Co. in West Grove, where the trials are held.

The winners must do more than survive to be chosen for the marketplace. They must emerge robust and clean, with a profusion of perfectly formed, beautifully colored blooms. And one other thing helps, something traditionalists could've told you from the get-go: fragrance. Too often in the mid-20th century, it was lost, as breeders scrambled to produce the tight buds, glamorous colors, and stiff stems that now define the perfect Valentine's Day rose.

Want to know about the importance of fragrance? Watch Hutton and his longtime friend and collaborator Alain Meilland, of Meilland International rose breeders of France, as they amble down the rows here. Hutton's tall, Meilland's short, but both dip and sway as they inch along, cupping blossoms in their hands and diving right in there to inhale.

Roses can smell like anything, and this is part of the fun — peaches, lemons, cloves, lavender, musk, chocolate, aftershave, impossible-to-describe, or nothing at all.

Both men suddenly stop to admire 'Francis Meilland,' which was bred by Meilland, commercialized by Conard-Pyle, and named for Alain's father on the centenary of his birth. Already the winner of several awards in Europe, it's a 2013 All-America Rose Selection, which — as a kind of Academy Award for roses in this country — is an honor rose breeders crave.

'Francis Meilland' is a hybrid tea, a class of garden rose long known for fussiness, delicate health, and killer looks. This one has a large bloom whose color would technically be called pink, but it brings to mind fine pearls and satin ballet slippers and pale shells on a beach. It also has above-average disease resistance and a deep, fruity fragrance that has Hutton and Meilland, two old hands at this, dipping down again and again for a fix.

'Francis Meilland' will hit the market in 2013, but Meilland says its high price tag means it will likely be destined for use only by floral designers. "You will never see it in pick-it-up bouquets in supermarkets," he says.

It's also the first hybrid tea to ace the AARS competition under no-spray conditions, no-spray being a lot like fragrance. Consumers are demanding it, an earthmoving development in a world once dominated by elite rose exhibitors and plant societies for whom spraying was de rigueur.

Hutton, who succeeded his father and grandfather as head of Conard-Pyle, remembers being sent inside the house when his dad, R.J. "Dick" Hutton, "dusted" the family roses. "My father had no mask, no gloves. Everybody sprayed everything back then," he says of the 1950s and 1960s, when just about every garden in the burgeoning American suburbs had to have one particular rose — a hybrid tea named 'Peace.'

It had a heady scent and pale yellow flowers edged in crimson. Of all the roses produced by the Meilland family — Alain Meilland is the fifth generation in the business, two nephews are the sixth — it remains the most famous. Sent out of France for safekeeping by Alain's father during the dark days of World War II, it was introduced to the United States by Conard-Pyle on April 29, 1945, the very day Berlin fell to the Allies.

Rosarians credit 'Peace' with single-handedly sparking the postwar rose rush in this country, and it remains, for many, a favorite.

Conard-Pyle found its own blockbuster in the Knock Out series of shrub roses, beginning with the original red, bred by Bill Radler and winner of the AARS designation in 2000, and continuing with six more in variations of pink and yellow. Tens of millions have sold; they're even more popular than 'Peace.'

And yet.

Mention Knock Out to an experienced gardener, or in an online forum, and prepare for takeoff. Yes, it's disease-resistant and drought-tolerant, it blooms continuously from May to frost, and it requires no deadheading or pruning, but its blooms are quite generic, there's little scent, and it's become so common that critics deride it as the omnipresent "Big Brother of rose bushes."

Hutton's version of "laughing all the way to the bank" consists of a pronouncement that Knock Out obviously strikes a chord with folks who are intimidated by the idea of growing roses. Perhaps, he muses, it should be considered a "gateway rose," just as marijuana is sometimes referred to as a "gateway drug."

"If people grow Knock Out and have a good experience, then they understand that, with some imagination and a little bit of work, they can grow lots of other kinds of roses, too," Hutton says, acknowledging that "Knock Out is not a subtle plant."

Both Hutton and Meilland, who met in 1958 when they were 7 and 18, respectively, are adamant that rose breeders, marketers, and sellers must do a better job of debunking the myth that all roses are hard to grow. And they need to offer customers not an "A-Z soup of everything out there," but a small assortment of maybe 20 roses that are proven successful in a particular region of the country.

That said, many modern varieties — not just Knock Out, but a slew of others bred for inexperienced gardeners with busy lives — are far more easygoing and better equipped to handle neglect in a home garden. Heck, look what they go through just to get to market!

Here in "rose hell," Knock Outs are mixed in with the (mostly) unnamed hoi polloi, serving as control plants. Knock Out's been rated 10 out of 10 for resistance to fungal diseases, a common problem in the hot, humid Philadelphia region in summer, and Hutton says any plant that scores below 7 or 7.5 won't make the cut.

On the other hand, and this comes as a bit of a surprise, he and Meilland sound way more forgiving of imperfection in the garden than the typical American consumer, who's notorious for wanting perfect-looking plants that bloom forever and require no care.

"You don't have to spray, but if you get black spot, you might lose maybe 20 percent of the foliage. That's OK," Hutton says, "because a rose is a plant. You can't hold it to the standard of a garden statue. Roses are going to look a little rough at the end of the year."

"Absolutely true," adds Meilland, who, though rumored to be semiretired, has big plans.

He wants to sell roses in Russia, Monaco, and Dubai, Africa, Asia, and Latin America, especially Mexico. He envisions rose bushes on every roof and high-rise balcony in population centers like Hong Kong, Singapore, and New York. Both he and Hutton salivate at the thought of selling to China.

"There's a lot to be done," Meilland says.

Meanwhile, the race is on to create a rose that combines the best qualities of the hybrid teas and the tough new shrub roses. Imagine 'Peace' with Knock Out grit.

Hutton's race is more immediate. Conard-Pyle's patent on Knock Out expires in 2018, and the pressure's on to find a worthy successor. "I'd be a very lucky man to have two Knock Outs in my professional career," he says, suggesting it's much more likely — and doable — to find 10 roses that each do one-tenth as well as Knock Out did.

"That's how," he says, "we'll keep the lights on for the next 20 years."

Contact Virginia A. Smith at 215-854-5720 or vsmith@phillynews.com.