Covering thirty-eight acres, Withdean Park is one of the most beautiful of Brighton's parks, carefully laid out with ornamental shrubs and flowers. This not a formal park with gravel paths and rectangular flower beds, but a delightful mix of open grassy areas, woodland, shrubberies and ponds. From 1960, Withdean Park was developed as a horticultural exhibit of specific genera, especially berberis, cotoneaster, viburnum, and floribunda roses, with new varieties added as they become available. The park is also famous for its collection of lilacs, the second largest in the world with over 250 types, which was designated by the National Council for the Conservation of Plants and Gardens as the National Reference Collection for the species and cultivars of the genus syringa (lilacs). Regrettably, the Parks Department has been unable to allocate sufficient funds to maintain the collection to a suitable standard, and the National Collection status was lost in 2009.
A delightful bog-garden with two lily-ponds has been laid out in a natural bowl near the south-western corner, on the site of the old manor house.