William McNab was born in Ayrshire in 1780. He became a gardening apprentice at the age of 16, and his abilities were such that by the age of 20 he obtained a position at the Royal Botanic Gardens at Kew. He became the foreman there in 1803.
In 1810, McNab was invited to take charge at the Royal Botanic Garden at Edinburgh. Although the salary was lower, the potential for development of the gardens was great. McNab developed the gardens very successfully between 1810 and 1820. Between 1820 and 1823, he supervised the transfer of the botanic gardens to a new site at Inverleith. He became an acknowledged expert in transplanting evergreen trees and shrubs. The new site provided new opportunities for McNab. Glasshouses were constructed for tender exotics, and he became especially associated with the cultivation of ericaceous plants from southern Africa.
William McNab died in 1848 and was succeeded as curator by his son, James. For more details on his life, please see: