[1][2][3][4] Andrews went to school at Rathnew, County Wicklow, Ireland, and studied at the National Botanic Garden, Glasnevin, where she graduated in 1973 with a First Class Honours in Amenity Horticulture and a Silver Medal awarded by the Irish Department of Horticulture.
She was promoted to Higher Scientific Officer in 1988 and took part in a collecting expedition to Sabah, Malaysia, concentrating on Ilex.
[8][9] In 2003 she left Kew becoming a full time freelance Consultant Horticultural Taxonomist in her own practise, and teaching courses on taxonomy for gardeners.
[2] Andrews has a long-term taxonomic research project into Ilex of Southeast Asia and in cultivation, as well as collaborating on Aquifoliaceae for Kubitzki's Families & Genera of Vascular Plants.
[10] Andrews was co-founder in 1988 and chairman (1988–1998) of (HORTAX), the Horticultural Taxonomy Group, a member of the editorial committee of Curtis's Botanical Magazine, the senior editor of Taxonomy of Cultivated Plants (1999), is an Honorary Research Associate at Kew, and sat on the ISHS Commission for Nomenclature and Registration.