Leinster Square Gardens was created when the surrounding imposing white stucco houses were built between 1856 and 1864. The garden is dominated by three majestic plane trees planted at that time, the central plane tree planted on 26 February 1887 in Queen Victoria's Golden Jubilee Year.
The garden was rescued from decline by a group of residents in the late 1970s. They replaced the railings that had been removed during WW2 and planted azaleas, rhododendrons and a collection of camellias. Much of this planting survives today.
By the early 2010s the garden was once again in need of attention. In 2015 it was extenstively restored to include new paths, an irrigation system, a small pavillion and new seating as well as a new planting plan. The garden is maintained by a once-weekly gardener.
Famous former residents of Leinster Square include the writer, ornithologist and founding member of the RSPB, William Henry Hudson at no. 11, and musician Sting at 28A.