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William Radler on Knock Out Roses

What Motivates William Radler to Breed Roses?

I have to say, when you love roses as much as I do and you plant as many as I do in my garden, most of them really need to be maintenance-free. William Radler is the creator and breeder of the Knock Out® Rose. Carefree and floriferous, it has changed the way gardeners use roses in the garden. He tells us more about his motivation to breed roses and what traits he was after when he developed the Knock Out® Rose.

What motivated you to breed roses?

I chaired my first rose show at age 19. I learned from all these other people that taught me how to do it. When they were getting in their retirement years, they were cutting back on their hobbies because it entailed too much work. I decided that one of the goals in my life was to breed the maintenance out of roses so I didn't have to cut back on my hobby. I started breeding in the mid-70s, and in 1989, I produced Knock Out® and it won an All-American Award and got on the market.

What parent roses did you use?

I took the best of the old, or wild, roses, and I crossed them with modern roses, hoping to get the traits of the two combined. And after that, it seems to be relatively easy to produce these roses.

Roses have a little fruit called a hip. The seed that's produced inside a hip will be extremely different than the rose it came from. There's going to be wide variability. If you select the best of the best, you're going to get rid of all the bad traits that make roses high-maintenance. If you want an exact duplicate of the rose, of course, you can bud graft or make cuttings.

What characteristics make Knock Out® Roses low maintenance?

With the Knock Out® series, we call these roses self-cleaning because the old bloom usually just falls off by itself and doesn't require dead-heading. And the next growth that's produced at the tips is going to produce nice, strong stems to produce more flowers. This is unheard of until the advent of Knock Out® Roses.

Knock Out® Roses are quite resistant to all the major diseases that are out there. And there's probably a lot more than the average person wants to know about.

They're winter-hardy. They might die back in the severe winter to the ground level, but they come back vigorously.

So, you've got a disease-resistant, attractive bloom that self-cleans, and, then, they also recycle quickly. Whereas a normal rose might produce 3 cycles of bloom during a season, Knock Out® Roses produce 4 or more.