Fluid flow physics in plants needs to be understood due to their complexity. These systems are not only multi-species, multi-scale, and multi-physics in nature but also involve intricate fluid/bio-structure interactions, highlighting the interdisciplinary nature of this research. Fluid flow hydrodynamics play a crucial role in plants by enabling water, nutrients, and hormones to transport throughout their tissues, essential for growth, survival, and reproduction on planet Earth and in outer space missions. The process of water movement through a plant, known as transpiration, relies on water molecules' cohesive and adhesive properties, creating a continuous column of water from the roots to the leaves. This movement is driven by a combination of capillary action, root pressure, and transpiration pull, with water evaporating from the stomata in the leaves. Additionally, the flow of phloem sap, which distributes sugars and other organic molecules from photosynthetic tissues to non-photosynthetic parts of the plant, is regulated by pressure differences in the plant's vascular system. Moreover, fluid flow aerodynamics also has a vital role in plants, for example, by transporting leaves and pollen particles from one vegetation region into another, by reducing overall carbon footprints, and by the impact on micro-climate, e.g., urban heat waves. Therefore, a comprehensive understanding of fluid flow dynamics in plants is not just beneficial but fundamental to advancing our knowledge in this field and potentially making discoveries. This special collection of articles presents state-of-the-art research in fluid flow dynamics and plants. The investigations made by the authors of the papers cover both experimental and computational studies around a range of plant applications, including hydrodynamics and aerodynamics flows. This unique topic has the potential to significantly advance our understanding of plant flow-biology and inspire new applications. A summary of the papers appearing in the special collection is presented below.