Rosa Melvina Breithaupt was born on on June 19, 1888 to Louis Jacob Breithaupt and Emma Alvarene Devitt. She was raised alongside her 7 siblings; Louise Evelyn; Emma Lillian; Martha Edna; Louis Orville; William Walter; Catherine Olive; and Paul Theodore.

Rosa was educated first locally in Kitchener, Ontario and later at the Ontario Ladies' College in 1908 and 1909 where she was a gold medallist in art. On October 10, 1917, she married Alfred Russell Hewetson of Brampton, Ontario whom she had met as a result of their involvement in the Christian Endeavour Movement. Together, Rosa and Alfred Russell had four children; Ruth Evelyn; Dorothy "Dodie" Elizabeth; Rosemary "Posey"; John Russell "Russ".

Following Russell's sudden death on February 8, 1928 of pneumonia, Rosa became active in his family's company, Hewetson Shoes in Brampton. Hoping to implement in Hewetson Shoes the co-operative ownership and profit-sharing plans in which her late husband had been interested, Rosa met with fellow-thinker, H. Hapgood, of the Columbia Conserve Co., and later with Professor Henri Lassere of the University of Toronto. In 1932, Rosa purchased the two-storey “Bickford” residence which was constructed in 1914 and had been Brigadier General Harold Child Bickford’s home. While organizing the Robert Owen Foundation in Toronto with Henri Lassere Rosa met her second husband, Herbert Spencer Clark. They married on August 77, 1932.

The Clarks’ dream was to transform their grand summer home and estate on the Scarborough Bluffs into a self sufficient co-operative for artists and craftsmen. Their goal was to encourage the Canadian arts and crafts movement and to preserve traditional skills and methods of fabrication. Recognizing the importance of the arts in society, they formed “The Guild of All Arts”, an artist’s co-operative and centre for Canadian artists and craftsmen based on the American Roycroft community model.

From 1932 to 1943, the Guild (Bickford) House became a residence for craftsmen and the Studio Building and the Bickford stables and garage accommodated their workshops. A few acres were planted with food crops and chickens and cows were kept to provide eggs and milk. In 1937 the ground floor addition on the north side provided increased dining facilities as well as a gift shop. This was followed by further expansion of the wings and new dormer additions to provide additional guest rooms. By the early 1940’s the Guild had become a country inn set amid working artisans surrounded by magnificent grounds.

Over the years, Rosa and Spencer acquired some 500 acres stretching from Kingston Road down to the lake and included one and a half miles of shoreline. They incorporated and adapted British "garden city" planning principles into the unique community of Guildwood Village, a Toronto suburb; they pursued artistic, cultural, and collecting interests and hobbies throughout the course of their long lives.

Rosa died on July 7, 1981 and is buried in Mount Pleasant Cemetery, Toronto. Spencer Clark died February 11, 1986 and is buried with Rosa.