The gardens were laid out in the late 19th and early 20th century by Henry Peak, the borough surveyor, using the best features from three prize winning plans and keeping some features which were already in place such as the paths and a circular flowerbed. The famous annual bedding was introduced in 1940, before this only a few beds were planted with annuals. A rustic bridge used to link the Bowling Green in the east to the castle grounds but there are now gates leading from one to the other, the subway was also built at this time. The public house which had been there became the head gardeners cottage, this was replaced in 1938. Public swimming baths were built in 1889 but demolished in 1971.
Gardeners Magazine of 1829 records Guildford Castle as the property of Elkins Esq. And states that the grounds have lately been enclosed and laid out as a garden, in a mixed style, combining crops, fruits, flowers and picturesque scenery. The Castle Keep, motte, surrounding land and the bowling green were purchased by the Guildford Corporation in 1885. The gardens were laid out and the grounds were re-opened in 1888. A bandstand was built above the green and trees, shrubs and roses adorned the grounds and divided the various areas. Local stone was used for the new boundary and retaining walls.
The war memorial was built in 1921, Second World War names were added to the memorial in 1995.