In recent years, he has focused his research on the limitations of different plants in their natural habitats, specifically examining physiological and morphological differences of asters in the forest and open fields. Currently, Pfitsch focuses on plant interactions with other organisms (specifically symbiotic fungi and bacteria) that help them meet those challenges.
His research has been supported by funds such as the Emerson Grant for Collaborative Research, and Howard Hughes Research. Currently, Pfitsch is working on a collaborative project with the Hamilton College Leonard C. Ferguson Professor of Biology Ernest Williams, The Nature Conservancy, and the NY State Department of Environmental Conservation on a project which has received funding from the National Wildlife Federation and The Nature Conservancy.
A member of the Environmental Studies Advisory Committee at Hamilton College, Pfitsch has published extensively. His articles were published in journals including Ecology and Oecologia, and he wrote a chapter for Tropical Alpine Environments: Plant Form and Function (Cambridge University Press).