The Grove of Green Holly (1967), which was a story about a group of 17th century travelling players who were hiding in a forest in Sussex from
Oliver Cromwell's soldiers, spawned her most famous work, the Mantlemass series (1970–1981) including her Guardian Prize-winning book. Some other books were
Hetty (1956),
Storm from the West (1963),
Three and One to Carry (1964), and
Charity at Home (1965). One of her last books,
The Forest - Ashdown in East Sussex, published by Sweethaws Press in 1989, gives a detailed account of
Ashdown Forest. In the introduction to the book,
Christopher Robin Milne notes that Willard had moved from her home on the Sussex Downs to the edge of Ashdown Forest in 1956 and that her new surroundings had provided the inspiration and setting for ten of her children's historical novels (eight in the
Mantlemass series and two others). It is evident by her own account in her book that she actively involved herself in the affairs of the forest. She was a representative of the forest Commoners elected to the forest's Board of Conservators in 1975, and she remained in that capacity for ten years. She tells how she was later heavily involved in the fundraising campaign which enabled East Sussex County Council to purchase the forest in 1988, enabling it to remain as a place of beauty and tranquility open to the public. ==List of selected works==