Forsyth was born at
Oldmeldrum in
Aberdeenshire, and trained as a gardener at the
Chelsea Physic Garden as a pupil of
Philip Miller, the chief gardener. He took over the chief gardening position in 1771 and became a mentor to
John Fraser. In 1784, he was appointed superintendent of the royal gardens at
Kensington and
St James's Palace, a position he kept until his death. In 1774 he created one of the first
rock gardens while curator of the Chelsea Physic Garden. His garden consisted of 40 tons of assorted stone collected from the roadside outside of the
Tower of London, some
flint and
chalk from nearby
downland, and some pieces of
lava collected from
Iceland. The garden failed to produce much serious growth. Forsyth created a '
plaister' in 1798 made of
lime,
dung,
ashes,
soapsuds,
urine, and other various components that was claimed to cure defects in trees and heal "where nothing remained but the bark." He received a grant of £1,500 from
British parliament to continue the creation of the plaister, as the nation was at war in 1799 with
Napoleon and needed sound timber to build ships, while the
Royal Forests were in poor condition. His great-grandson was the gardener and landscape architect
Joseph Forsyth Johnson (1840–1906). Johnson was in turn the great-grandfather of the entertainer
Bruce Forsyth (1928–2017). ==Selected works==