Brookes was influenced by painters such as Piet Mondrian and Ben Nicholson, and brought abstract and modernist principles to garden design.
In 1954, after visiting gardens in Southern France and studying horticulture, Brookes enrolled in a three-year apprenticeship in Nottingham Parks Department.
Four years in the offices of Dame Sylvia Crowe and Brenda Colvin, renowned landscape architects, provided Brookes with further experience and an introduction to London, and he subsequently started his own practice.
Upon his return, Brookes resumed his practice and established the Clock House School of Design at Denmans Gardens, near Chichester in West Sussex.
He quickly began designing, lecturing, and teaching in the United States and Canada, and subsequently as far afield as Japan, Argentina, South Africa, Australia, and Russia.
Brookes clearly articulated his guiding design principle – that "gardens are fundamentally a place for the use by people" — in his first book, Room Outside, published in 1969 and revised in 2007.
In this way, the grid principle evolved into a methodology in which geometric curves and squares could be introduced to create simple flowing lines and defining spaces.
[7] At the time she and her husband acquired the garden, it had suffered years of neglect and the house associated with the property had been used by as a mess for the officers from nearby Tangmere Air Base during World War II.
Brookes was intrigued by her bold planting style and use of gravel, which he'd been using since the early 1960s, and was drawn to the garden's moderate climate and beautiful location at the foot of the West Sussex South Downs.