Green urban spaces are a vigorous part in cities development, all over the world (Swanwick, Dunnet, & Wooley, 2003). These spaces are persistently constructed and negotiated over a creative process, which includes a network of actors, such as clients, designers, constructors, and users. This thesis addresses this process - with a case study of landscape architects in Stockholm, and their practice of creativity. The landscape architects present one group of actors involved in the process, where they design urban spaces for the future through their creative work. It begins with a mental image, an idea, and ends with a built site, a designed space. In reference to practice theory (Ortner, 1984 and 2006) and the biosocial becomings approach (Ingold, 2013), I analyze how creativity as a practice is socially produced by history, culture and power, through the biosocial growth of the creative agent, the landscape architect. Referring to Hallam and Ingold ́s definition (2007, p. 3), I understand creative practice as an improvisational process. I argue that creativity is accumulated, i.e. a becoming practice amongst becoming creative agents. While investigating the practice of creativity through a traditional participant observation, I primarily focus on sounds, where I listen to the practice, and use it as a method of collecting empirical data. With that method, I enrich the registration of sensor impressions (Borneman & Hammoudi, 2009, p. 19) during my fieldwork, providing a sonic dimension to the knowledge of creative practice amongst landscape architects.