Professor Weston co-founded and currently leads a large multidisciplinary research team, the Plant Interactions Research Group, investigating plant/plant, plant/microbial, plant/herbivore and insect/soil interactions with a focus on invasion ecology and genetics, chemical ecology and signalling, use of biocontrol organisms for pest management, allelopathy and plant interactions with herbivores resulting in toxicity.

Professor Weston has focused on the study of bioactive natural plant products that are involved in plant defence strategies, with a particular emphasis on bioherbicides and phytotoxins. Ground-breaking research techniques employing analytical chemistry, metabolomics, separation science, genomics and population and field ecology has resulted in advances in our understanding of how plants employ secondary products as chemical signalling agents, in defence strategies against pests including weeds and grazing herbivores, localization of these metabolites in the plant and soil rhizosphere and their impact on the function and dynamics of soil microbial communities. Recent studies have also focused on a greater understanding of their role in toxicity to grazing livestock and specific mode of action as herbicides, cytotoxins and photosensitisers.