Guillaume Beaumont was a French gardener, active in England from the 1680s to 1727. He may have worked under Le Notre in France. In England, he was employed by Colonel Graham, first as a nurseryman at Bagshot, during the reign of James II, and later, after 1688, as head gardener at Levens Hall in Cumberland, where he laid out a fine topiary garden and series of avenues.
Sources:
Hadfield, Miles, Robert Harling and Leonine Highton, British Gardeners: A Biographical Dictionary (London: A. Zwemmer Ltd., 1980), p. 33.