As a teenager, May showed an interest in art; however due to a sense of family responsibility, May, the fifth of ten children, postponed academic studies until her mid-twenties to look after her younger siblings.
May was based in Quebec early in her career, then worked as a teacher from her studio in Montreal, at the Elmwood School in Ottawa.
She was associated with the National Gallery of Canada in Ottawa, Ontario for a decade, returned to Quebec and ended her career in Vancouver, British Columbia.
Her art was originally influenced by her avid interest in French Impressionism, but her mature style owed much to the Group of Seven and more international modernist trends.
[3] He later became a successful real estate developer and moved her and the rest of her family to a more prosperous neighbourhood in Montreal called Westmount.
Though Henrietta displayed an active interest in art throughout her early years, she did not pursue formal education until she was in her mid-twenties.
She delayed her education in order to help take care of her nine younger brothers and sisters while her parents worked trying to provide for them.
[4] In 1902 she became one of the first female students enrolled in the Art Association of Montreal (AAM) (1909 – 1912) under teachers Alberta Cleland and William Brymner.
May was influenced by Brymner's teachings of French modernism, including Impressionism and Post-Impressionism and his encouragement for students to find their own individual style.
In 1916, after May returned to Montreal, she joined other female artists who worked on commissioned pieces specifically about women's involvement in the First World War.
One of her major works was a detailed six-by-seven foot canvas entitled Women Making Shells (1919) honouring munitions workers in a factory.
[11] During May's commissioned employment with the Royal Canadian Academy, she made 250 dollars per month, a large fee at that time.
The Beaver Hall Group was extremely progressive at the time for allowing women to join and have important roles and positions.
[13] Though the group officially disbanded around 1924, a majority of the female members continued to do artistic work afterwards, nearly all of them foregoing marriage or childbearing to do so.
May's Melting Snow (1925) was a reflection of the dancing waters and lyrical mountains surrounded by flat colours and hills.
[23] In 2015, the Musée des Beaux-Arts Montréal organized a multi-museum tour of a show containing May's work among others: 1920s Modernism in Montreal: The Beaver Hall Group.
After the dissolution of the Beaver Hall Group's studios, she retained close personal friendships with the remaining female artists, including Lilias Torrance Newton, Mabel Lockerby, Anne Savage, Sarah Robertson, and Nora Collyer.
She spent some time in France, came back radiant - loved life - painted in the landscapes of the Eastern Townships, where she built up her singing happy pictures.