This book deals with mathematical models of plant growth and their applications, which consider architectural development as well as plant growth that includes the production and distribution of synthesized biomass (source-sink relationships). The interaction between plant architecture and growth contributes to the plasticity of plants in response to the environment and to the mode of cultivation. The modeling of plant development (organogenesis) and growth (photosynthesis) requires a multidisciplinary and a multiscale approach (botany, agronomy, applied mathematics, computer science) according to the principles of integrative biology (Chauvet). Botanical knowledge on the concepts of herbaceous and woody plant architectures, as well as eco-physiological knowledge used in agronomy, are exposed.