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.
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.”
Knock Out is also the first rose to be awarded “super star” status by EarthKind, the organization that recognizes roses that are outstanding performers in the garden as well as environmentally responsible. EarthKind recommends it for virtually any task from mass plantings to lining walkways to adding a splashy exclamation point wherever needed.
Gardeners who’ve helped create Knock Out mania insist that it thrives on neglect and is virtually indestructible.
I can attest to that. Eight years ago, I was the ungrateful recipient of a Knock Out rose. “The lady at the nursery raved about it,” my friend told me. “So we decided to get you one for your birthday.”
I said I was delighted, but in reality was wondering what I was going to do with this homely shrub rose. It didn’t fit in with my prissy hybrid teas. It couldn’t possibly live next to my frilly English roses.
So I banished it to a lackluster, semishaded corner of the garden. Undaunted, the little rose grew and bloomed happily.
Later, since spraying wasn’t an issue, I decided I’d move the rose out by my pond. The bud union split in half when I dug it up. I planted both pieces just before my husband accidentally trimmed them with the weed whacker.
Even a foot of brackish water delivered by hurricane Isabel couldn’t kill them. Every other plant in the vicinity died, but Knock Out bounced back.
Impressed by the rose’s tenacity, I recently removed some hybrid teas and replaced them with Double Red Knock Outs.
So far they’re performing beautifully and don’t need to be coddled. Thus it appears I’m a reluctant convert. From now on, Knock Out, I’m going to be in your corner.
Knock Out’s brothers and sisters
Although the original Knock Out still reigns supreme, new varieties have been developed that boast the same disease resistance and tolerance to heat, humidity, and cold. They grow to approximately three feet in height and are recommended for areas that get five or more hours of direct sunlight.
Pink Knock Out – A “sport” or natural mutation of the original bush in a bright pink hue. It thrives in humidity and is an ideal choice for the Deep South.
Blushing Knock Out – The pastel-pink blooms change to shell pink as they age. It is also naturally mildew resistant.
Rainbow Knock Out – Coral pink blooms are tinged with rich yellow at the base. More compact and free flowering than earlier varieties.
Double Red Knock Out – Features the same characteristics as the original but with twice as many petals. Fluorescent cherry-red blossoms cover the bush all season long. Foliage turns deep maroon in the fall.
Double Pink Knock Out – A sister to Double Red with hot pink blooms. It requires no maintenance and is self-cleaning (the petals fall from the plant by themselves; they dont’ have to be cut off).
Sunny Knock Out – Only limited availability this year, but debuting nationwide next year, Sunny features dark green semiglossy foliage and pastel yellow blooms that fade to a creamy white. Grows to approximately four feet and has a slight fragrance.