Hans M. Heybroek (born 1927, Bussum) is a Dutch botanist best known for his research into the genus Ulmus at the Dorschkamp Research Institute for Forestry & Landscape Planning. Until his retirement in 1992, he was responsible for the raising and release of numerous elm hybrid cultivars, notably 'Columella'. Specializing in phytopathology, Heybroek also investigated the Coral Spot fungus Nectria cinnabarina in elm. In 1960 he travelled to the Kashmir to search for a frost-hardy form of the Himalayan Elm Ulmus wallichiana as a source of anti-fungal genes, for use in the Dutch elm research programme.