Kordes is a world renown nursery based in Germany that started in the late 1800's and for over the past several decades have focused almost exclusively on roses. Some of their most famous roses include the fragrant red hybrid tea 'Crimson Glory' from 1935 (it became the standard fragrant deep crimson hybrid tea rose for decades for both garden use and as a commercial cut flower) and Iceberg (introduced 1958, white floribunda rose). About 20 years ago Kordes recognized the growing public concern over the use of pesticides and had the foresight to recognize the opportunity to highly prioritize disease resistance in their rose breeding program. They chose to eliminate the use of fungicides on the rose seedling populations meant for garden use and today have some of the most disease resistant garden roses in the world.
Kordes had an ongoing agreement with a US nursery to introduce their roses into the North American market, but that firm had their own rose breeding program and didn't introduce many Kordes roses into the marketplace. With that business relationship ended, Kordes roses are beginning to flood the US marketplace.
Reports from the New York Botanical Garden, Boerner Botanical Gardens, gardeners in Canada, and preliminary Earth-Kind® observational plantings point to great potential in these roses and the initiation of the Earth-Kind® Kordes Rose Trials using the full Earth-Kind® testing methodology (compost and mulch, spacing, blocking and randomization, etc.) has begun. This same set of Kordes roses are also planted at other sites in River Falls, WI, Milwaukee, WI, and Dallas, Texas. The Dilworth site is the northernmost trial site and is the critical site to learn the cold tolerance extremes of these roses as well as their performance in high pH soil. Additionally, the trial site is large enough to include not only Kordes cultivars, but also a handful of additional rose cultivars by other breeders showing promise for their disease resistance in preliminary trials. Through this multi-year trial it will be exciting to learn which roses that possess the disease resistance and climatic adaptability to be great additions to the gardens of northwest Minnesota.
-David C. Zlesak, University of Minnesota Extension Educator, Northern Earth-Kind® and Kordes Rose Trial Coordinator.