Balfour was educated at the Edinburgh Academy from 1864 to 1870. At this early stage his interests and abilities were in the biological sciences, which were taught to him by his father. Due to his father's post as Professor of Botany at Edinburgh, the young Balfour was able to visit the Edinburgh Botanical Gardens, not open to the public at the time. Balfour studied at the University of Edinburgh, from which he graduated with first class honours in 1873, and at the universities in Würzburg and Strasbourg. In 1874 Balfour participated in an astronomical expedition of 1874 to Rodrigues. Though the stated aim of the mission was to observe Venus, Balfour used the opportunity to investigate the local flora, and on his return, the fieldwork he had carried out permitted him to gain his doctorate. In 1879, his father resigned the chair at Edinburgh, Glasgow professor Alexander Dickson was appointed in his place, and the younger Balfour was promoted to the chair of Regius Professor of Botany, Glasgow in Glasgow from 1879 to 1885. He also went on to lead an expedition to Socotra in 1880. In 1884, he was appointed Sherardian Professor of Botany at the University of Oxford. In the same year he married Agnes Boyd Balloch. It was, however, after his return to Edinburgh to take up his father's old chair as Professor of Botany from 1888 to 1922 that Balfour left his mark, as he was also appointed 9th Regius Keeper of the Royal Botanic Garden Edinburgh. His father had greatly enlarged the botanical gardens during his tenure, but Balfour completely transformed them. Having put their finances on a safer footing by transferring them to the crown, Balfour engaged himself in a major reform of the gardens, establishing a proper botanical institute, and largely redeveloping the layout of the gardens to have a proper arboretum, building new laboratories and improving scientific facilities. He was awarded KBE in the 1920 civilian war honours list. He died at Court Hill, Haslemere in Surrey.
Specific interests
Balfour's interest in Sino-Himalayan plants also put him in contact with botanist and plant collector Reginald Farrer. Farrer provided valuable information to Balfour and the Royal Botanic Garden Edinburgh by sending him his plant illustrations together with the field notes, botanical specimens and seeds he had collected.
1921: Awarded Honorary Doctor of Laws degree, University of Edinburgh
Commemoration
The Benmore Estate was gifted to the nation by Harry George Younger of the Younger's family, and in 1928 he had the Bayley Balfour Memorial Hut, dedicated to Sir Isaac, placed in Puck's Glen. It was designed by Sir Robert Lorimer, with wooden panels using every variety of timber grown at Benmore. It also commemorated the contribution of James Duncan, a previous owner of the estate. The woodland was taken over by the Forestry Commission, which dedicated the area around the glen to the memory of Sir Isaac, while the central part of the estate was opened in 1929 as the Younger Botanic Garden, the first outstation of the Royal Botanic Garden Edinburgh. In 1968 the Bayley Balfour Memorial Hut was restored, and moved to a new site in the walled garden of Benmore House. Balfour is commemorated in the scientific name of a species of Socotran lizard, Mesalina balfouri.
