Ferris performed in her younger years at the Mercury Theatre in Auckland, and later with various regional companies in the UK. She played motherly Ma Larkin in the ITV series "The Darling Buds of May", which ran from 1991 to 1993. She has also acted in a succession of television dramas, including "Meantime", in which she played the Cockney mother of Phil Daniels and Tim Roth, "Connie", "Hardwicke House", "Oranges Are Not the Only Fruit", "Where the Heart Is" and "Paradise Heights". From 2003 to 2006, she played the gardening sleuth, Laura Thyme, in "Rosemary & Thyme".