[3] Guilfoyle settled in the Tweed River valley where he grew tobacco and sugar cane and first met the noted German botanist, Ferdinand von Mueller.

In April 1873 Mueller created the genus Guilfoylia and described William Guilfoyle as "distinguished as a collector [who] evidenced great ardour" and held high hopes for his collecting ability.

Over the next 35 years, Guilfoyle sculpted sweeping lawns, meandering paths and glittering lakes, creating a series of vistas offering a surprise around every corner.

The swamp and lagoon were separated from the Yarra River under the direction of Carlo Catani (1852–1918), a civil engineer with the Public Works Department, allowing Guilfoyle to create the chain of ornamental lakes further adding to the beauty of the gardens.

[4] Another, the "Temple of the Winds" monument was dedicated to Governor Charles La Trobe and erected by William Guilfoyle in the Botanical Gardens.

[4] In addition to these structures, Guilfoyle added a series of large iron archways to highlight entry to the rest houses and to mark points of transition like 'doorways'.

The garden contains The Federal Oak which was planted in 1890 by Sir Henry Parkes; a plaque recognising the efforts of Vida Goldstein; and an 'oriental-style' pavilion.

Guilfoyle also wrote extensively for the Bankers' Magazine of Australasia, the Victorian Naturalist, and two guide books (1902, 1908) to the Melbourne Botanic Gardens.