William Brodrick Thomas was a garden designer active in the mid-19th century. He was based at 52, Wimpole Street, London. His grandfather was Lord Midleton, who had an estate in County Cork, Ireland. His terms were five guineas per day plus expenses.
He designed an ornamental lake with Pulham rockwork at Sandringham, Norfolk, for the Prince of Wales, who referred to Thomas as 'a gentleman not to be described as inexpensive'.
He laid out the grounds of Benenden, Tunbridge Wells, Kent. Among his other works were the asylum grounds at Colney Hatch, London (1849-51).
In the 1840s or 1850s he laid out a large and elaborate ramped parterre under the west front of Baronscourt, County Tyrone for the Earl of Abercorn. Thirteen gardeners were required to maintain this feature, which was removed in 1913.
In 1866 he advised at Powerscourt, County Wicklow, Ireland, where he drew a plan which was not implemented.
He was then involved with Glaslough, County Monaghan, Ireland, where he advised Colonel Leslie. Thomas marked trees proposed for removal by placing a calling card on each tree. After his departure Leslie removed the cards and proceeded no further.
In 1879 Thomas designed the new garden for Lord Iveagh at St. Stephen's Green, Dublin, for its new use as a public park. The design included a lake with Pulham rockwork. Thomas was too ill to supervise the implementation of the project, which was carried out by William Sheppard.