Biomimicry and computational design are two growing fields of research and practice in architecture for their potential in performative and sustainable design, among many other benefits. Cooling loads are posing serious energy problems in hot climatic cities as in Cairo and Alexandria. Attempting to solve these problems, this research turned to botanical inspirations for ideas in order to improve thermoregulation of the building skin. One of these ideas was chosen and implemented using computational software in the design of a parametric vertical shading screen for a typical office room in Cairo. The challenge was to minimize cooling loads as much as possible without compromising daylight requirements. An evolutionary solver was used to optimize results and environmental simulations were performed before and after the proposed screen to assess its performance and evaluate this biomimetic-computational approach to design.