From thousands of roses, maybe a few will be stars

Will Radler thinks he has about 3,500 roses in his garden, and most of them are headed to the compost pile. 

No plant is too precious if you’re a plant breeder. The culling is frequent, brutal and spares only the best. Radler, the Greenfield, Wis., plant breeder and former director of Milwaukee’s Boerner Botanical Garden, grows about 500 rose seedlings of his creation each year. If it’s a good year, about two of those will have the chance to make it to market.

Radler’s most famous creation — the Knock Out rose that was the first easy-care, long-blooming rose to be available to gardeners — was introduced 25 years ago in 2000, but it was a mere seedling in 1989. It made the cut to earn its place in his garden year after year, moving with him to his current two-acre property in 1992.

That property is now also the home of thousands of other roses, each vying to become the next Radler-bred rose to end up in garden centers. Radler’s property is easily identifiable in an otherwise normal suburban neighborhood that just happens to have a small botanical garden growing in the middle of it. A large garden off his house’s back patio is arranged with a formal rose garden aesthetic, each plant marked by a neatly printed label with a series of numbers that correspond to a year of breeding, parent plants and other details.

Roses are not limited to the rose garden on this property though. Everywhere you turn, Radler has squeezed in a rose. Flanking the front door is ‘Cancan,’ a stunning climber that varies from hot pink to purple depending on exposure, that is no longer available for sale. Another climber with enormous pink flowers crawls up the wall along the garage door. 

But in addition to roses, there are other plants, including a collection of Penstemon, interesting conifers, a Kerria japonica that blooms all season and an eclectic collection of Wisconsin native plants. As Radler walks through his garden, he checks the labels on notable plants, in one case an enormous hosta, only to be reminded that he bred it. Plant breeders rarely limit themselves to a particular species. 

Even on a casual stroll through the garden, Radler’s breeder instincts are piqued, as he notes seedlings of one plant that appear to be remarkably hardy, or an otherwise beautiful, established rose that is flowering freely in its last year in the garden. The fault that has resigned such a beautiful plant to death row — Velcrolike thorns that mean it doesn’t stand a chance in most people’s gardens. That Kerria (a little known shrub rarely seen in garden centers)? He’s already sent cuttings to Starr Roses and Plants, which he works with, to be propagated and grown out for testing.

In addition to willingness to be a ruthless judge of your own work, plant breeding is about observation. The little details that go unnoticed by regular gardeners every day spark inspiration in plant breeders. And some day, perhaps long after they are gone, that detail might lead to a plant that finds a home in millions of gardens. 

Radler’s garden is open to the public a few times each summer. For dates, go to www.roseinnovations.org.