Low-code development platforms (LCDPs) offer organizations the potential to reassign time-intensive software development tasks from professional to citizen developers, freeing up resources for professionals while empowering domain experts. However, while software can be rapidly built through citizen development (CDD), organizations must look beyond implementation and consider whether software built by individuals with limited technical backgrounds is scalable and durable. In this study, we investigate the scalability of CDD in organizations by conducting a multivocal literature review, integrating both the current phenomenon (CDD) as well as related, established research streams like end-user development. We identify four dimensions affecting CDD scalability and four temporal stages of CDD maturity, and present these as a CDD scaling framework. Moreover, we identify three overarching themes in scaling CDD. Finally, we present an integrated research agenda based on the CDD scaling framework and overarching themes.