This man was William Kent, and he invented what become known as the British landscape garden.
Kent's ideas for garden design soon spread, not the least because of the men he was working with at Stowe, namely James Gibbs and Lancelot "Capability" Brown, who would become the greatest of all British garden architects and whose 300th birthday we celebrate this year.
One of the intriguing things about landscape gardens are certainly the small buildings – the follies – dotted around the landscape. They reflect contemporary tastes, but can also be wildly eccentric. At Stowe we find neoclassical designs such as the Temple of Concord and Victory…
On some estates, the kitchen gardens were integrated into the whole design of the grounds, and the hothouses in particular became lavish buildings which any owner would be proud to show to his guests. One of the plants cultivated in hothouses was the pineapple, which ideally would be ripe in time for Christmas. The 4th Earl of Dunmore seems to have had a particular liking for pineapples – a preference that is reflected in the very design of one of his large hothouses: the Dunmore Pineapple.
William Kent: Designing Georgian Britain https://www.youtube.com/watch?v=K99dalOrR1c
Alan Titchmarsh gets a chance to look at Capability Brown's plans for the park and gardens of Belvoir Castle (pronounced "Beaver" Castle) – and they're pretty big: https://www.youtube.com/watch?v=Gd7hglXqtic
Capability Brown's EPIC engineering: A look at the artifical lakes at Wotton House https://www.youtube.com/watch?v=O0fsB5cSaUQ
And if you really, really, REALLY want to dig into garden history, check out the Garden History Lecture series organized by Claremont Fan Court School:
Lecture 1: Subverting the Palladian: William Kent and the Eclectic Urge https://www.youtube.com/watch?v=hWxAaxUNnB8
Lecture 2: The Omnipotent Magician: Lancelot "Capability" Brown https://www.youtube.com/watch?v=iEsWWiYW8gE
Stowe: Grecian Valley Looking towards the Temple of Concord and Victory: By Philip Halling, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=13521107
Stowe: The Rotondo from across the Eleven Acre Lake: By Philip Halling, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=4391378
Gothic Temple, Stowe: By Amanda Lewis, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=4391286
Stowe: The Chinese House: By Philip Halling, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=8397611
The Wimpole Folly: By Users Tysto, Nickarse2412 on en.wikipedia - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=1076760
The Dunmore Pineapple: By giannandrea - Own work, CC0, https://commons.wikimedia.org/w/index.php?curid=12863790