A large portion of Clarke's music features the viola, as she was a professional performer for many years. Much of her output was written for herself and the all-female chamber ensembles she played in, including the Norah Clench Quartet, the English Ensemble, and the d'Aranyi Sisters. She also toured worldwide, particularly with cellist May Mukle. Her works were strongly influenced by several trends in 20th-century classical music. Clarke also knew many leading composers of the day, including Bloch and Ravel, with whom her work has been compared.