William George Spencer Cavendish, 6th Duke of Devonshire,  – 18 January 1858), styled Marquess of Hartington until 1811, was a British peer, courtier, nobleman, and Whig politician. Known as the "Bachelor Duke", he was Lord Chamberlain of the Household between 1827 and 1828 and again between 1830 and 1834. The Cavendish banana is named after him.(21 May 1790
Born in Paris, France, Devonshire was the son of William Cavendish, 5th Duke of Devonshire, and Lady Georgiana, daughter of John Spencer, 1st Earl Spencer. He was educated at Harrow and at Trinity College, Cambridge. He lost both his parents while still in his youth; his mother died in 1806 and his father in 1811 when, aged 21, he succeeded to the dukedom. Along with the title, he inherited eight stately homes and some 200,000 acres (809 km² or 80,900 ha) of land.
Politically Devonshire followed in the Whig family tradition. He supported Catholic emancipation, the abolition of slavery and reduced factory working hours. He held office as Lord Chamberlain of the Household under George Canning and Lord Goderich between 1827 and 1828 and under Lord Grey and Lord Melbourne between 1830 and 1834. In 1827 he was sworn of the Privy Council and made a Knight of the Garter. He was appointed Ambassador Extraordinary to the Russian Empire on the coronation of Tsar Nicholas I in 1826.
Devonshire was also Lord Lieutenant of Derbyshire between 1811 and 1858 and carried the Orb at the coronation of George IV in 1821. However, increasing deafness from an early age prevented him from taking an even greater part in public life.
Devonshire had a major interest in gardening and horticulture, and devoted himself sedulously to the care and nurture of his vast estates. His major projects including the wholesale rebuilding of the village of Edensor, and significant improvement to his several stately houses and their gardens. He befriended Sir Joseph Paxton, then employed at the Royal Horticultural Society's Chiswick Gardens, located close to Devonshire's London estate Chiswick House, and appointed him his head gardener at Chatsworth House in 1826, despite Paxton being only in his early twenties at the time. Paxton greatly expanded the gardens at Chatsworth, including the construction of a 277 foot long conservatory, which served as a model for The Crystal Palace constructed in London's Hyde Park.
Devonshire, himself a keen horticulturalist, was elected President of the Royal Horticultural Society in 1838, a position in which he served for twenty years until his death. It was this interest which led him to establish the Royal Botanic Gardens at Kew as a national botanic garden. The world's most commercially exploited banana, the Cavendish, was named in his honour. He had acquired an early specimen, which he raised in his glasshouse, and this plant is the progenitor of almost all the worldwide varieties of Cavendish banana.
He also travelled extensively.
In 1845, Cavendish published a book called Handbook to Chatsworth and Hardwick. It was privately printed and provided a history of the Cavendish family's two primary estates: Chatsworth House and Hardwick Hall; the handbook was praised by author Charles Dickens.
Much of Devonshire's private correspondence, including letters to his mistresses (one of whom he installed nearby), was destroyed by his Victorian relatives. He intended to marry Lady Caroline Ponsonby, his cousin, but she married William Lamb, which he found devastating.
Devonshire died at Hardwick Hall, Derbyshire, in January 1858, aged 67, and left an estate valued at £500,000 in his will. As he was unmarried the dukedom passed to his cousin William Cavendish, 2nd Earl of Burlington. His junior title of Baron Clifford fell into abeyance between his sisters, Georgiana, Countess of Carlisle, and Harriet, Countess Granville.
- K. D. Reynolds, ‘Cavendish, William George Spencer, sixth duke of Devonshire (1790–1858)’, Oxford Dictionary of National Biography, Oxford University Press, Sept 2004; online edn, Jan 2008 accessed 6 June 2010
- "Cavendish, William [George] Spencer, Marquess of Hartington (CVNS807WG)". A Cambridge Alumni Database. University of Cambridge.
- Biography of Devonshire on Orchidologists website
- "No. 18360". The London Gazette. 11 May 1827. p. 1033.
- "No. 18241". The London Gazette. 25 April 1826. p. 965.
- leighrayment.com Peerage: Desborough to Dorchester[Usurped!]
- Lankester Botanical Garden (2010). "Biographies" (PDF). Lankesteriana. 10 (2/3): 183–206, page 186. Archived (PDF) from the original on 23 May 2014.
- details of the taxonomic naming of the cavendish banana
- Newsletter of the Geological Curators Club Archived 16 July 2011 at the Wayback Machine, Vol 1, No. 8, 1976. Retrieved 24 June 2011
- "Handbook of Chatsworth and Hardwick". Chatsworth. Retrieved 14 April 2021.
- "The Devonshire Family Collections at Chatsworth". Archives Hub. Retrieved 14 April 2021.