Thomas Hayton Mawson was born on 5 May 1861 in the village of Scorton, south of Lancaster, the eldest son of John William Mawson, cotton warper, and his wife, Jane Hayton and was educated at the local church school. At the age of twelve he joined his uncle’s building business in Lancaster where he obtained the rudiments of architectural drawing. Two years later he returned home to help his father set up a nursery in Ingleton, Yorkshire, but the business struggled even before John Mawson’s death in 1877.
The family decided to seek work in London. Thomas was sent ahead and secured work with John Wills, a well-known floral decorator, later moving to Hale Farm Nurseries Tottenham. However, it was his ambition to become a garden designer and he appeared to have succeeded in this when he was offered a partnership with a firm of Surrey contractors. On the strength of this he married in 1884, but while on honeymoon in Windermere he was told that the offer had been withdrawn. Forced to reconsider his future plans, he decided to set up a nursery and contracting business with his two brothers, in Windermere. Such a move made sound business sense. Windermere did not exist before the arrival of the railway in 1847. When the proposed extension to Ambleside was finally abandoned by the railway company in the face of local opposition, the development of a new town at the railhead began in earnest. The railway also attracted a new breed of in-comer to the Lake District - industrialists from the Lancashire and Yorkshire anxious to invest their wealth in second homes and associated gardens.
By 1885 a suitable plot of land had been leased and Mawson Brothers nursery established. From the outset it was agreed that Thomas was to develop the garden design side of the business while his brothers Robert and Isaac were to be responsible for contracting work. Once both were established the two sides of the firm were to separate, the formal division being made in 1895. In 1887 he obtained his first major commission, the gardens at Bryerswood, Far Sawrey, for the Bolton bleacher, J R Bridson. The architect for the house was the Bolton architect Richard Knill Freeman. who, on the strength of this, obtained a further commission at the nearby Graythwaite Hall, Newby Bridge, for Colonel Sandys. Here responsibility for the supervision of construction was delegated to his assistant, Dan Gibson with Mawson again involved in alterations to the gardens. Mawson and Gibson would subsequently enjoy a brief partnership. Over the next twenty-five years Mawson designed over one hundred gardens for private clients. In the Lake District these included glasshouses in the walled gardens at Holehird for the Salford brewer William Grimble Groves; Brockholes (1899-1900, architect Dan Gibson) for WHA Gaddum of Manchester; Cringlemire, Troutbeck, (c1900) for Henry Martin, a Halifax manufacture; Langdale Chase (1890), Cragwood (1909 architect Frank Dunkerley); Blackwell (1902, architect M H Baillie Scott) for the Manchester brewer Sir Edward Holt; Moor Crag (architect CFA Voysey) and Rydal Hall in Ambleside (1909) . Contacts thus made led to other garden commissions throughout the United Kingdom.
In 1902, at a time when the Local Government Board was seeking to reduce unemployment by works of public utility, he was requested to provide plans for the laying out of a public park at Hanley, closely followed by a similar request from Burslem town council. In the same year he designed a park for Barrow in Furness although work was not commenced until 1907-8. In 1904 he was requested to prepared plans for the development of Pittencrieff Park at Dunfermline. His scheme was not progressed, however, it brought him into contract with Andrew Carnegie. William Lever, later Lord Leverhulme, employed Mawson extensively, including the formation of a public park at Rivington near Bolton and the laying out of extensive gardens associated with Royton cottage on the hillside above.
Between 1905 and 1914 Mawson visited North America, designing gardens in Baltimore and New York. In Canada he was involved in major town planning schemes in Banff, Ottawa, Vancouver, Calgary, and Regina though these were only partially implemented or not carried out. However, they were of sufficient quantity to warrant the opening of a branch office in Vancouver. European schemes included gardens for Queen Alexandra in Denmark, a garden outside Paris and in Prussia, and the Peace Palace gardens at The Hague, won in competition while in 1917 the firm were involved in the re-planning of Salonika after a disastrous fire. However, Mawson considered his most prestigious commission to be the royal gardens and a park system in Athens for the king of Greece, from 1913, though construction work was never begun, partially as a result of the outbreak of war.
During World War One, Mawson became concerned about the plight of disabled servicemen. In his book 'An Imperial Obligation: Industrial Villages for Partially Disabled Soldiers' (London: Grant Richards, 1917) he advanced a scheme for purpose-built villages to house disabled ex-servicemen. Although he received widespread support, his ideas were opposed by the Ministry of Pensions and only Westfield, Lancaster was built, the funds raised through private donations.
On 1 August 1884 Mawson married Anna (b. 1862/3), a nurse, daughter of Edward Prentice, surgeon, of North Walsham. They had four sons and five daughters, one of whom died in infancy. The three eldest sons followed their father into the family business, while his youngest son, Thomas Hayton Mawson, (1899- 1992) took over the running of Lakeland Nurseries. Three of his daughters established Thornton Art Industries in Lincolnshire. About 1898 Mawson built a holiday bungalow on the foreshore at Hest Bank, later extended to three times its original size. Five minutes walk from Hest Bank station on the main line to London, Mawson found this more convenient for his travels and the family lived here more and more. A new office was opened in Lancaster and operations in Windermere scaled down.
Mawson was elected an honorary member of the Royal Institute of British Architects in 1903 and became a member of the Art-Workers' Guild in 1905. He was made a freeman of the City of London in 1917 and an honorary liveryman of the Worshipful Company of Gardeners. In 1921 he became a fellow of the Linnean Society. In 1923 he was elected president of the Town Planning Institute and the following year he was appointed to the Royal Fine Arts Commission. In 1929 he became the first president of the Institute of Landscape Architects. Mawson published two main works: The Art and Craft of Garden Making (1900), which ran into five editions, and 'Civic Art: Studies in Town Planning, Parks, Boulevards and Open Spaces' (London: B.T. Batsford, 1911), which summarises his views on Town Planning. From 1910 to 1924 he lectured regularly at the school of civic design, Liverpool University.
In 1923 Mawson was diagnosed with the early stages of Parkinson’s Disease. Thereafter he took an ever decreasing role in the active running of the business. He had formally retired by 1928, although he is still recorded as inspecting the drawings for most schemes until the early 1930s. Assisted by Edward Prentice Mawson he published the fifth and last edition of “The Art and Craft of Garden Making” in 1925 and dictated his autobiography published in 1927. He died at Applethwaite, Hest Bank on 14 November 1933, and was buried at Bowness Cemetery. Anna outlived her husband by over twenty years and died in 1955, at the age of 92.