Hillel Oppenheimerm, born and educated in Germany, became the keeper of the Aaron Aaronsohn Herbarium in Zichron Yaacov in 1926. He joined Hebrew University as a botanist and plant physiologist, and established the horticultural, physiological, and genetics station at the Jewish Agency's Agricultural Experiment Station at Reḥovot, which later became the Faculty of Agriculture. He founded The Palestine Journal of Botany. His was an authority on citrus crops. In 1959 he received the Israel Prize in Agriculture.