An important task assigned to the colonial botanical gardens was dealing with malaria, the largest obstacle to colonial expansion. Heyne was placed in charge of the Lalbagh botanical garden till 1812. He did a great deal of collecting at Coimbatore and Bangalore and compiled a large collection of plant specimens which were forwarded to London. He collected more than 350 species from the Western Ghats and more than 200 species were named by him. He sent many of his Indian botanical specimens to the German botanist Albrecht Wilhelm Roth, whose work Novae plantarum species praesertim Indiae orientali (a book of Indian flora) is largely based on Heyne's botanical specimens.