How did woody plants originate? The answer varies. Whereas most woody species have woody ancestors, others evolved from non-woody (herbaceous) ancestors. This repeated origin of woodiness (estimated at 700 cases) is an example of a little-understood phenomenon: convergent evolution. A plant family that stands out is the mustard family, well-known from popular crops like broccoli, radish and arugula. This study unravels where, when and why woodiness evolved within the family. Since a shift towards woodiness is a possible adaptation to drought, this study will provide insights into ways to breed more drought-resilient crops within the mustard family.