John Cathcart Wason was born on the Corwar estate, Colmonell, Ayrshire, Scotland, in November 1848, the son of Euphemia McTier and her husband, Peter Rigby Wason. His father was a barrister and a successful farmer who converted much of the Corwar estate from moor to arable land; he had also served as a member of Parliament. Cathcart Wason, as he was generally known, was educated at Laleham and Rugby School, before emigrating to Canterbury, New Zealand, in late 1868.
In February 1869 Wason paid £10,000 for the Lendon run of 20,000 acres, including 1,250 freehold. It was on the south bank of the Rakaia River, exposed to prevailing northwest winds, but with good loess soils. Wason promptly renamed it Corwar and soon became renowned locally as a tree planter and expert farmer. He grew the first large shelter belts south of the Rakaia and was among the early users of Pinus radiata. His oaks, walnuts and poplars gave 'a homely and English-like appearance to the neighbourhood.' By 1884 600 acres of plantings were bringing 'refreshing' relief from 'the bare monotony of the open plain'. Wason grew extensive crops of wheat, imported Lincoln sheep breeding stock, exported refrigerated merino mutton, and, believing that 'a farm is in every sense of the term a manufactory', used the local water race to power agricultural machinery. He had consolidated Corwar as a middle-sized freehold estate of 5,226 acres by 1882, although he continued to buy and sell land thereafter.
In the mid 1870s Wason established Barrhill, one of the few estate villages in central Canterbury. Some houses were built using the estate's Pinus radiata; the schoolroom and teacher's residence (erected at government expense) and the Anglican church (built in conjunction with other local landowners) are early examples of the use of concrete. The highest population of the village was about 50, but it had begun to decline within 10 years.
Wason planted the site with a variety of trees in an unusual pattern, possibly intended to convey a religious symbolism. Four outer avenues, each planted with a different type of tree, form a square, which is bisected by two avenues forming a cross. At the intersection of the cross stand three circles of oaks containing, respectively, the church, the schoolroom, and a house.
Wason's community interests were focused in Ashburton county. He served on the first Ashburton County Council between 1876 and 1879, and was chairman of the South Rakaia Road Board from 1874 to 1877 before being forced to resign when members objected to his autocratic tendencies. At various times he was president of the Ashburton Racing Club and of the Ashburton Caledonian Club, vice president of the Ashburton Acclimatisation Society and a steward of the Canterbury Jockey Club.
In 1876 Wason won the Coleridge parliamentary seat by seven votes. A commanding speaker, he campaigned 'for local government under centralism.' He urged the adoption of compulsory, secular state education and advocated closer settlement through the auctioning of leasehold runs. He was appointed government whip in July 1877. In 1881–82 he sat for the Wakanui seat, but the election was declared invalid owing to errors by the returning officer. He did not stand again until 1893, when he ran a vigorous campaign for the Ashburton seat, referring to the Liberals' programme as 'socialistic nonsense'. He was defeated, but was returned for Selwyn in the 1896–99 Parliament after a more circumspect campaign. In Parliament he argued against the policy of overseas borrowing, something he had himself favoured in the 1870s.
Wason travelled overseas on a number of occasions. On 18 June 1873 he married Alice Seymour Bell, in Sydney, Australia. In 1886 he was in London and was elected a fellow of the Royal Geographical Society, although he made no contribution to the geographical field. The following year he was admitted to the Bar at the Middle Temple, like his father and brother before him. Unlike them, however, he did not practise. In 1895 he was in London again.
In 1900 Wason sold up his property in New Zealand and returned to Scotland. That year he was elected as Liberal MP for Orkney and Shetland, and bought a London house and a property in Ayrshire not far from the original Corwar. At Westminster he joined his brother, Eugene Wason, who was chairman of the Scottish Liberal members from 1908 to 1918.
Cathcart Wason died in London on 19 April 1921. He was survived by his wife; it seems that they had no children. Tribute was paid to Wason in the House of Representatives as 'no ordinary man'. He was remembered for his dominating presence, his height of about six feet six inches contributing to this. On one occasion he was said to have dealt with a troublemaker at a Christchurch ball by picking him up and standing him on his head in an enormous dish of trifle. He was also recalled as a lover of flowers (although oddly, not of trees), as a pioneer settler with Vogelite sympathies, and while in the House of Commons, as a supporter of New Zealand's interests.
Although Wason's house at Corwar in Canterbury burnt down not long after his departure, the public buildings at Barrhill survive. The Pinus radiata plantings have long since been cut, but the oaks, poplars and other trees remain, still giving this part of the Canterbury Plains the character he originally sought to create.