He has been breeding roses since 1984 and has introduced several rose cultivars including Above and BeyondTM , a new hardy apricot colored climber through Bailey Nurseries (2015), and the Oso Happy™ series of shrub roses through Proven Winners. David coordinates the Northern Earth-Kind® Rose Trials, is a board member of the new American Rose Trials for Sustainability®, and works with colleagues at the University of Minnesota on characterizing new rose viruses and studying resistance to rose black spot disease.