Robert MacKellar was born in Scotland (Argyll area) and his early years were spent under the tutelage of his father – Duncan (who worked at the Kirkland Lodge Gardens, Edinburgh). He then worked at Floors Castle, Chatsworth, a nursery in Chelsea and Drayton Manor.
He spent some two years at Kew and then moved to the position of head gardener at the agricultural college at Cirencester. From there, he moved to Elvaston and thence to Sir James Watts’ garden at Abney Hall (Cheadle). The 1901 Census records that Robert was living in the gardener’s cottage at Abney Hall with his widowed father, Duncan, and niece, Maggie (born in Brixton). He retained the position of head gardener until his early death in January 1903.
He gave time to lecturing and demonstrations to improve the knowledge of gardeners in his area, and exhibited successfully at the Lancashire Horticultural Shows. He was the first in the U.K. to fruit and raise seedlings of Cycas revoluta.
Information from : http://www.kewguild.org.uk/media/pdfs/v2s11p109-41.pdf