How Cultivars Are Selected

Earning the Earth-Kind® Rose Designation

The decision as to whether a particular rose cultivar is worthy of receiving the prestigious Earth-Kind® designation is, on average, based on eight years of research and field trial data. Specifically, this long-term, labor-intensive process features four years of randomized, replicated research at Texas A&M AgriLife Center – Dallas in which plants were evaluated and data collected by a team of seven Ph.D.s which included horticulturists, plant pathologists, a soil scientist, and an entomologist.

These scientists have coauthored abstracts and peer-reviewed scientific journal articles documenting these research results which have been published as follows:

  • Mackay, W.A., S.W. George, C. McKenney, J.J. Sloan, R.I. Cabrera, J.A. Reinert, P. Colbaugh, L. Lockett and W. Crow. 2008. Performance of Garden Roses in North Central Texas under Minimal Input Conditions. HortTechnology 18(3): 417-422.
  • Colbaugh, P.F., W.T. Crow, W.A. Mackay and S.W. George. 2005. Varietal reaction of selected rose varieties to Alternaria petal blight. Biological and Cultural Tests for Control of Plant Diseases. Vol. 20 p. 18. A.P.S. Press.
  • Colbaugh, P.F., W.T. Crow, W.A. Mackay and S.W. George. 2005. Varietal reaction of selected rose varieties to black spot. Biological and Cultural Tests for Control of Plant Diseases. Vol. 20 p. 17. A.P.S. Press.
  • Colbaugh, P.F., W.T. Crow, W.A. Mackay and S.W. George. 2005. Varietal reaction of selected rose varieties to powdery mildew. Biological and Cultural Tests for Control of Plant Diseases. Vol. 20 p. 19. A.P.S. Press.
  • Mackay, W.A., C.M. McKenney, P.F. Colbaugh, S.W. George, J.J. Sloan, and R.I. Cabrera. 2005. Performance of Garden Roses Under Minimal Input Conditions in North-Central Texas. HortScience (Abstr.) 40 (3): 881.
  • Mackay, W.A., W. Crow, P. Colbaugh, S.W. George, C. McKenney, J.J. Sloan, and R. Cabrera. 2001. Performance of 33 Rose Cultivars in North-Central Texas Under Minimal Input Conditions. Southern Region ASHS. HortScience (Abstr.) 36(5): 841.

This initial research was followed by four years of confirmational field trials at such diverse Texas locations as Abilene, Addison, Beaumont, Conroe, El Campo, Ft. Worth, Houston, Mineola, Odessa, Rosenberg, Tomball, and Tyler representing USDA Cold Hardiness Zones 7 to 9 and soils ranging from acid sands to highly alkaline clays. During all eight years of testing, no pesticides, chemical or organic, were ever applied to the research and trial roses. The success of this approach to growing landscape roses contributes significantly to the consumer’s desire for beautiful, lower-maintenance, environmentally-responsible landscape plants.

The rationale and results of Earth-Kind rose research in Texas are so compelling that scientists at six other universities (Colorado State, Iowa State, Kansas State, LSU, University of Minnesota, and the University of Nebraska) have now initiated similar Earth-Kind research programs. Members of this new team have already coauthored two scientific publications which further support the Earth-Kind rose research program. These publications are:

  • Harp, D., D. Zlesak, G. Hammond, S. George, and W. Mackay. 2009. EarthKind™ Rose Trials – Identifying the World’s Strongest, Most Beautiful Landscape Roses. Floriculture and Ornamental Biotechnology 3 (1): 166-175.
  • Zlesak, D.C., J. Griffin, D. Harp, K. Cue, N. Howell, T. Blunt, R. Nelson, and S. George. 2008. Initiation of the northern EarthKind™ rose trial. HortScience 43: 1144-1145.

In addition to a sound field research and trialing foundation in Texas, cultivar performance input is obtained from a 14-member advisory panel composed of rose experts before a cultivar receives the Earth-Kind designation. The advisory panel includes: Texas A&M AgriLife Research and Extension personnel (Dr. Brent Pemberton, rose researcher, and Tom LeRoy, Extension horticulturist), industry representatives (Mark Chamblee, Chamblee’s Roses, Mike Shoup, The Antique Rose Emporium, and Beverly Welch, The Arbor Gate), rosarians (Gaye Hammond, past president of the Houston Rose Society, and Clyde Cannon), and authors (Dr. Bill Welch, Liz Druitt, and Kathy Huber). Input is also sought from County Extension Horticulture Agents, such as Deborah Benge-Frost, Melissa Sturdivant, and Micah Meyer, who served as Earth-Kind Rose Trial site coordinators.

With these intense, multi-year research and field trials, plus the wealth of experience provided by advisory panel members, rose cultivars are chosen to receive the Earth-Kind designation. This process makes Earth-Kind roses the most thoroughly tested, research proven, and environmentally responsible landscape roses recommended for use in Texas landscapes.

Prepared by
Dr. Steve George
Extension Horticulturist
Texas AgriLife Extension Service
Texas A&M System
December 14, 2009

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