Plant grafting is an important horticultural technique involving the physical joining of two plants. It has been practiced for thousands of years and today, is commonly used in orchards for dwarfing trees and in vineyards to provide disease resistance. Despite the widespread use of this technique, we know little about the process of graft junction formation at the molecular, developmental or genetic levels. I will present research using Arabidopsis thaliana as a model for graft formation. Using fluorescent dyes, hormone-responsive reporters, and cell-identity reporters has allowed a detailed characterization of vascular reconnection and gene activation. A reverse genetics approach has identified plants unable to graft and uncovered a genetic pathway important for graft formation. These results provide a developmental framework for graft formation and point to the critical role of hormone response in this process.