Fothergill made a study of
conchology and
botany in his leisure time. In 1762, he bought
Upton House in
West Ham,
Essex (now in
Greater London), where he built up an extensive
botanical garden and grew many rare plants obtained from various parts of the world (now
West Ham Park). In the garden, with its
glasshouses,
John Coakley Lettsom (1744–1815), a Quaker physician and a protégé of his, exclaimed that "the sphere seemed transposed, as the Arctic Circle joined with the equator". Lettsom published a catalogue of Fothergill's garden: ''Hortus Uptonensis, or a catalogue of the plants in the Dr Fothergill's garden at Upton, at the time of his decease anno 1780
. Fothergilla'' is named in his honour. The standard author abbreviation Foth. is used to indicate him when citing a botanical name. He was elected a
Fellow of the Royal Society in 1763 and became a member of the
American Philosophical Society in 1770. Fothergill was the patron of
Sydney Parkinson, the South Sea voyager, and of
William Bartram, the American botanist in his southern travels of 1773–1776. A translation of the Bible, known as the
Quaker Bible, made by Anthony Purver, was fashioned and printed at his expense. He founded
Ackworth School, Pontefract, Yorkshire in 1779. John Fothergill died in London on 26 December 1780 aged 68, of urinary retention perhaps linked with prostate cancer.
Fanny Burney, having earlier described him as "an upright, stern old man... an old prig," later recorded when she was his patient: "He really has been... amazingly civil and polite to me... as kind as he is skilful." His niece Betty Fothergill described him in her journal as "surely the first of men. With the becoming dignity of age he unites the cheerfulness and liberality of youth. He possesses the most virtues and the fewest failings of any man I know". Barbara Wheeler's father was attended during his illness by Dr. Fothergill in 1777. She and her brother,
Daniel Wheeler, were inspired to convert to
Quakerism after the meeting. In 1815, she thus refers to the Quaker physician in her autobiography: ==See also==