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Winner by a Knock Out

A rose that’s won millions of fans across the globe

By Lynn HuntContributor to The Christian Science Monitor / June 13, 2008

LOVELY TO LOOK AT: Rainbow Knock Out rose won an All-America Rose Selections award for its low-maintenance and lovely flowers.

Courtesy of Conard-Pyle/Star Roses


An unlikely superstar was introduced to the gardening world in the year 2000: a humble shrub rose named Knock Out, which sported less than 10 petals and didn’t even smell like a rose, yet had attributes few other roses could claim: It was disease- and drought-resistant, oblivious to humidity, tolerated some shade, and was winter-hardy to Zone 4.

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It even tidied itself up after blooming, eliminating the need for extensive pruning. Best of all, it produced a parade of showy red blooms from May till November.

Even though such a plant sounded too good to be true, the American public was willing to give it a whirl, snapping up 250,000 Knock Out bushes the first year on the market.

The little rose didn’t disappoint and soon became the darling, first of home gardeners then of commercial landscape designers. Sales have expanded, too, topping 5 million last year in the United States (and even more worldwide).

It’s an amazing success story, considering that the seed that launched the Knock Out empire came close to being tossed in the trash.

When he was only 9, Bill Radler – who eventually hybridized Knock Out – used his allowance to buy his first rose. By the time he graduated from high school, he was tending to more than 150 bushes and winning fistfuls of blue ribbons at Wisconsin rose society shows.

But the work that went into keeping all those roses disease-free became tiresome. He started thinking about creating a new kind of rose that wouldn’t require chemical spraying or winter protection.

The hybridizing process can be tedious and painstaking. Roses are cross-pollinated, hips are allowed to form, and the resulting seeds are planted and closely observed. Then comes more cross-breeding, more hips, more seeds, and – for the most part – disappointment.

After 15 years of effort, Radler planted the only seed harvested from the hip of a straggly bush he almost got rid of. The plant that grew from that solitary seed was sent to the Conard-Pyle Co. for evaluation and won an All-America Rose Selections award within a decade.

Steve Hutton, president and CEO of Conard-Pyle Co., is a third-generation nurseryman who believes Knock Out is the most universally consistent rose he has seen in his career: “It’s perfect for people who didn’t think they could grow roses and for those who want to add a touch of dependable color to the garden without worrying about constant care.

Knock Out became an instant hit with commercial landscape firms. “They need to be able to install their gardens and walk away,” Mr. Hutton says. “They can’t keep coming back to spray and prune. Knock Out is maintenance-free, yet has strong curb appeal.”