In the 17th century, this area in the south west corner of Richmond Park was known as The Sleyt. This is the name usually used for boggy ground or an open space between woods or banks.
By 1771, it is shown on maps as Isabella Slade . Isabella may have been the wife or daughter of a member of staff. But it is more likely to be a corruption of the word isabel, which was used as far back as the 15th century to mean dingy or greyish yellow - the colour of the soil in this part of the park.
In 1831, Lord Sidmouth, the park deputy ranger, fenced off 17ha (42 acres) of the Isabella Slade . He planted oak, beech and sweet chestnut trees as a crop for timber and gave the area the name it has today.
The present garden of clearings, ponds and streams was established from the 1950s onwards. It is largely the work of George Thomson, the park superintendent from 1951-1971. Along with his head gardener, Wally Miller, he removed Rhododendron ponticum from large areas and replaced it with other rhododendron species. They established evergreen Kurume Azaleas around the Still Pond and planted other exotic shrub and tree species.
The main stream through the garden from Broomfield Gate was dug in 1960 and the plantation was enlarged to include Peg's Pond.
More recently, in 1989, a wild stream was dug in the northern section and this has now been colonized by ferns, water plantains and brook lime. The Bog Garden was reconstructed in 2000.