His summer estate Hartekamp, south of Haarlem in Heemstede near Bennebroek, had a rich variety of plants and he engaged the Swedish naturalist Carl von Linné ("Carl Linnaeus"), who stayed at his estate from 1736 to 1738, to write Hortus Cliffortianus (1737), a masterpiece of early botanical literature published in 1738, and for which Georg Dionysius Ehret did the illustrations.
His grandfather, Englishman George Clifford I, moved from Stow (where his father was rector) to Amsterdam around 1640, beginning an Anglo-Dutch trading and banking dynasty.
He was an important friend and seed supplier for botanist Herman Boerhaave, whose summer home (and garden) at Oud Poelgeest was just a short trip away by trekschuit along the Haarlem-Leiden canal known as the Leidsevaart.
Clifford died in 1760 and left the business to his sons George IV (1708-1757), Jan (1710-1772), Henry (1711-1787) and the estate to Pieter (1712-1788).
Clifford's herbarium was acquired by Joseph Banks in 1791 who passed it on to the British Museum of Natural History, where it is published online.