In the Main, or Library, Quad there is a cedar planted by Harold Macmillan in 1976, after an old cedar was victim of a winter storm. Another tree, a "Picea likiangensis" (var. "rubescens"), was planted in 2007 on the chapel lawn, providing Somerville with an outdoor Christmas tree. The library border of lavender and "Agapanthus" references the bluestocking reputation of Somerville, and the tory blue "Ceratostigma willmottianum" is planted outside the Margaret Thatcher Centre. The garden outside the Thatcher Centre, now dedicated to Lisa Minoprio, was originally designed by the former director of the Oxford Botanic Garden and Lecturer in Plant Sciences Timothy Walker, and retains yellow and blue as the thematic colours.