Begonia is the world’s fastest-growing genus and a focus of intense taxonomic research. To support this, a stable and useful sectional classification is needed. This paper reviews the feasibility and challenges of creating an infrageneric classification for Begonia based on phylogenetic data, and how to overcome phylogenetic and taxonomic conflict. In particular, it (i) tests genus-wide patterns of incongruence between phylogenies based on the nuclear, chloroplast and mitochondrial genomes; (ii) explains organelle inheritance and its contribution to phylogenetic incongruence, and (iii) presents a manifesto for a workable and stable subgeneric classification in light of the above and lays the foundation for a collaborative Begonia Phylogeny Group.