William J. Radler

William J. Radler

Years: 

unknown

Year Hutchinson Medal awarded:

2015

American rosarian, breeder, and creator of the Knock Out® Rose, the best‑selling rose series in the United States

William J. Radler’s innovations redefined rose breeding, making low‑care, disease‑resistant roses the modern standard. His Knock Out® family remains the most commercially successful landscape rose line ever introduced. He continues breeding new rose varieties through Rose Innovations and international trialing programs.

Radler earned a Bachelor of Science in Landscape Architecture from the University of Wisconsin–Madison. He worked 26 years with the Milwaukee County Park System and served 13 years as director of Boerner Botanical Gardens before retiring early to focus on rose breeding. Radler began hybridizing roses in his basement, using a ping‑pong table as a workbench and milk jugs for water runoff. Later, he founded Rose Innovations, LLC to support breeding, trials, and R&D.

Key Contributions:

  • After 15 years of breeding, Radler produced the breakthrough seedling “89‑20.1” in 1989.
  • He has developed over 50 patented roses, including: Double Knock Out®, Coral Knock Out®, Peachy Knock Out®, and Rainbow Knock Out®.
  • Radler has also introduced Rosetta (garden mum, 1999), Verbena Sweet Thing™ (2010), and Tradescantia Amethyst Mist™ (2013)

Other Major Honors:

  • All‑America Rose Selections Award (2000) and numerous U.S. and international awards for the Knock Out® rose. More than 90 million have been sold worldwide.
  • All‑America Rose Selections (2000)
  • Genoa International Rose Competition Prize (2001)
  • ADR Award, Germany (2002) American Rose Society David Fuerstenburg Prize (2003)
  • Australian Gold Medal (2003)
  • Portland International Rose Test Garden Gold Medal (2003)
  • Great Rosarian of the World Award (2008)
  • Knock Out® rose selected as the Official Flower of the Beijing Olympics (2008)
  • GCA Jane Righter Rose Medal (2011)
  • World Federation of Rose Societies Hall of Fame (2018)
  • Nominated for the 2020 National Garden Clubs Award of Excellence